#ifdef ssu1
#define _GLIBCXX_DEBUG
#endif
#undef NDEBUG
 
#include <algorithm>
#include <functional>
#include <numeric>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <cassert>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <bitset>
#include <sstream>
 
using namespace std;
 
#define fore(i, l, r) for(int i = (l); i < (r); ++i)
#define forn(i, n) fore(i, 0, n)
#define fori(i, l, r) fore(i, l, (r) + 1)
#define sz(v) int((v).size())
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define mp make_pair
#define X first
#define Y second
 
#if ( _WIN32 || __WIN32__ )
    #define LLD "%I64d"
#else
    #define LLD "%lld"
#endif
 
typedef long long li;
typedef long double ld;
typedef pair<int, int> pt;
 
template<typename T> T abs(T a) { return a < 0 ? -a : a; }
template<typename T> T sqr(T a) { return a*a; }
 
const int INF = (int)1e9;
const ld EPS = 1e-9;
const ld PI = 3.1415926535897932384626433832795;
 
/*
    This is just to check correctness of input
 
*/
void ensure(bool value){
    if(!value){
        fprintf(stderr, "Assertion failed");
        throw;
    }
}
void ensure(bool value, string message){
    if(!value){
        fprintf(stderr, "Assertion failed. Message = %s", message.c_str());
        throw;
    }
}
int readInt(int l, int r){
    int x;
    if(scanf("%d", &x) != 1){
        fprintf(stderr, "Expected int in range [%d, %d], but haven't found!", l, r);
        throw;
    }
    if(!(l <= x && x <= r)){
        fprintf(stderr, "Expected int in range [%d, %d], but found %d!", l, r, x);
        throw;
    }
    return x;
}
int readInt(int l, int r, string name){
    int x;
    if(scanf("%d", &x) != 1){
        fprintf(stderr, "Expected int %s in range [%d, %d], but haven't found!", name.c_str(), l, r);
        throw;
    }
    if(!(l <= x && x <= r)){
        fprintf(stderr, "Expected int %s in range [%d, %d], but found %d!", name.c_str(), l, r, x);
        throw;
    }
    return x;
}
li readLong(li l, li r){
    li x;
    if(scanf(LLD, &x) != 1){
        fprintf(stderr, "Expected long long in range ["LLD", "LLD"], but haven't found!", l, r);
        throw;
    }
    if(!(l <= x && x <= r)){
        fprintf(stderr, "Expected long long in range ["LLD", "LLD"], but found "LLD"!", l, r, x);
        throw;
    }
    return x;
}
li readLong(li l, li r, string name){
    li x;
    if(scanf(LLD, &x) != 1){
        fprintf(stderr, "Expected long long %s in range ["LLD", "LLD"], but haven't found!", name.c_str(), l, r);
        throw;
    }
    if(!(l <= x && x <= r)){
        fprintf(stderr, "Expected long long %s in range ["LLD", "LLD"], but found "LLD"!", name.c_str(), l, r, x);
        throw;
    }
    return x;
}
const ld __EPS__ = 1e-15;
ld readDouble(double l, double r){
    double x;
    if(scanf("%lf", &x) != 1){
        fprintf(stderr, "Expected double in range [%lf, %lf], but haven't found!", l, r);
        throw;
    }
    if(!(l <= x + __EPS__ && x <= r + __EPS__)){
        fprintf(stderr, "Expected double in range [%lf, %lf], but found %lf!", l, r, x);
        throw;
    }
    return x;
}
ld readDouble(double l, double r, string name){
    double x;
    if(scanf("%lf", &x) != 1){
        fprintf(stderr, "Expected double %s in range [%lf, %lf], but haven't found!", name.c_str(), l, r);
        throw;
    }
    if(!(l <= x + __EPS__ && x <= r + __EPS__)){
        fprintf(stderr, "Expected double %s in range [%lf, %lf], but found %lf!", name.c_str(), l, r, x);
        throw;
    }
    return x;
}
const int __MAXBUF__ = (int)1e7;
char __buf__[__MAXBUF__];
string readString(char lfc, char rgc, int lfn, int rgn){
    ensure(scanf(" %s ", __buf__) == 1, "Expected string, haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "String have incorrect length");
    forn(i, sz(ans))
        ensure(lfc <= ans[i] && ans[i] <= rgc, "String contains incorrect characters");
    return ans;
}
string readString(string pat, int lfn, int rgn){
    ensure(scanf(" %s ", __buf__) == 1, "Expected string, haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "String have incorrect length");
    forn(i, sz(ans))
        ensure(find(all(pat), ans[i]) != pat.end(), "String contains incorrect characters");
    return ans;
}
string readString(char lfc, char rgc, int lfn, int rgn, string name){
    ensure(scanf(" %s ", __buf__) == 1, "Expected string " + name + ", haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "String " + name + " have incorrect length");
    forn(i, sz(ans))
        ensure(lfc <= ans[i] && ans[i] <= rgc, "String " + name + " contains incorrect characters");
    return ans;
}
string readString(string pat, int lfn, int rgn, string name){
    ensure(scanf(" %s ", __buf__) == 1, "Expected string " + name + ", haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "String " + name + " have incorrect length");
    forn(i, sz(ans))
        ensure(find(all(pat), ans[i]) != pat.end(), "String " + name + " contains incorrect characters");
    return ans;
}
string readLine(char lfc, char rgc, int lfn, int rgn){
    ensure(gets(__buf__) != NULL, "Line expected, haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "Line have incorrect length");
    forn(i, sz(ans))
        ensure(lfc <= ans[i] && ans[i] <= rgc, "Line contains incorrect characters");
    return ans;
}
string readLine(string pat, int lfn, int rgn){
    ensure(gets(__buf__) != NULL, "Line expected, haven't found");
    string ans = __buf__;
    ensure(lfn <= sz(ans) && sz(ans) <= rgn, "Line have incorrect length");
    forn(i, sz(ans))
        ensure(find(all(pat), ans[i]) != pat.end(), "Line contains incorrect characters");
    return ans;
}
string readLine(){
    ensure(gets(__buf__) != NULL, "Line expected, haven't found");
    string ans = __buf__;
    return ans;
}
char readChar(){
    char c;
    ensure(scanf(" %c ", &c) == 1, "Non-whitespace character expected");
    return c;
}
char readWChar(){
    int ans = getchar();
    ensure(ans != EOF, "Character expected");
    return (char)ans;
}
 
const int MOD = 3;
const int NMAX = 200000;
 
int z[NMAX], sm[NMAX][MOD], pf[NMAX];
 
inline int cnt_pf(int lf, int rg, int val){
    if(lf > rg)
        return 0;
    return sm[rg][val] - (lf == 0 ? 0 : sm[lf - 1][val]);
}
 
int main(){
#ifdef ssu1
    assert(freopen("input.txt", "rt", stdin));
    //assert(freopen("output.txt", "wt", stdout));
#endif
 
    string s = readLine('0', '9', 1, 100000);
 
    forn(i, sz(s)){
        pf[i] = (s[i] - '0') % 3;
        if(i > 0){
            pf[i] = (pf[i] + pf[i - 1]) % 3;
            memcpy(sm[i], sm[i - 1], sizeof(int) * 3);
        }
        if(!(i + 1 < sz(s) && s[i + 1] == '0'))
            sm[i][pf[i]]++;
    }
 
    li ans = 0;
 
    memset(z, 0, sizeof z);
    int l = 0, r = -1;
    forn(i, sz(s)){
        z[i] = (i <= r ? min(r - i + 1, z[l + (r - i)]) : 0);
        while(i - z[i] >= 0 && i + z[i] < sz(s) && s[i - z[i]] == s[i + z[i]])
            z[i]++;
 
        int curd = (s[i] - '0') % 3;
        int want = ((3 - curd) * 2 + curd) % 3;
        int lf = i - z[i] + 1;
 
        ans += cnt_pf(max(0, lf - 1), i - 1, (pf[i] - want + 3) % 3);
        if(lf == 0 && s[0] != '0' && pf[i] == want)
            ans++;
        if(s[i] == '0')
            ans++;
 
        if(i + z[i] - 1 >= r)
            l = i - z[i] + 1, r = i + z[i] - 1;
    }
 
    memset(z, 0, sizeof z);
    l = 0, r = -1;
    fore(i, 1, sz(s)){
        z[i] = (i <= r ? min(r - i + 1, z[l + (r - i) + 1]) : 0);
        while(i - z[i] - 1 >= 0 && i + z[i] < sz(s) && s[i - z[i] - 1] == s[i + z[i]])
            z[i]++;
 
        if(z[i] > 0){
            int want = 0, lf = i - z[i];
            ans += cnt_pf(max(0, lf - 1), i - 2, (pf[i - 1] - want + 3) % 3);
            if(lf == 0 && s[0] != '0' && pf[i - 1] == want)
                ans++;
        }
 
        if(r < i + z[i] - 1)
            l = i - z[i], r = i + z[i] - 1;
    }
    cout << ans << endl;
    return 0;
}