#include <bits/stdc++.h>
 
using namespace std;
 
const int MaxN = (int)4e6 + 10;
const int INF = (int)1e9;
const int MOD = (int)1e9 + 7;
 
int fc[MaxN], rf[MaxN], inv[MaxN];
int kdp[3018];
 
int calcZ(int lx, int ly, int rx, int ry) {
	if (lx > rx || ly > ry) {
		return 0;
	}
	return 1LL * fc[(rx - lx) + (ry - ly)] * rf[rx - lx] % MOD * rf[ry - ly] % MOD;
}
 
int calc(int lx, int ly, int rx, int ry, int c) {
	int kx = ly + c - 1, ky = lx - c + 1;
	return (calcZ(lx, ly, rx, ry) - calcZ(kx, ky, rx, ry) + MOD) % MOD;
}
 
int main() {
// 	freopen("input.txt", "r", stdin);
	fc[0] = rf[0] = 1;
	for (int i = 1; i < MaxN; ++i) {
		inv[i] = i == 1 ? 1 : 1LL * (MOD - MOD / i) * inv[MOD % i] % MOD;
		fc[i] = 1LL * i * fc[i - 1] % MOD;
		rf[i] = 1LL * inv[i] * rf[i - 1] % MOD;
	}
	int m, q, p, c;
	scanf("%d%d%d%d", &p, &q, &c, &m);
	assert (1 <= m && m <= 3000);
	assert (0 <= q && q <= 2000000);
	assert (0 <= p && p <= 2000000);
	assert (0 <= c && c <= 2000000);
	set < pair < int, int > > s;
	int mi = INF;
	for (int i = 1; i <= m; ++i) {
		int x, y;
		scanf("%d%d", &x, &y);
		if (y == 0) {
			mi = min(mi, x);
		}
		assert (0 <= x && x <= 2000000);
		assert (0 <= y && y <= 2000000);
		if (x - y >= c && x <= p && y <= q) {
			s.insert(make_pair(x, y));
		}
	}
	if (p == 0 && q < mi) {
		printf("1\n");
		return 0;
	}
	if (mi <= c || s.count(make_pair(p, q)) || p - q < c) {
		printf("0\n");
		return 0;
	}
	vector < pair < int, int > > pts = vector < pair < int, int > > (s.begin(), s.end());
	pts.push_back(make_pair(p, q));
	for (int i = 0; i < (int)pts.size(); ++i) {
		kdp[i] = calc(c, 0, pts[i].first, pts[i].second, c);
		for (int j = 0; j < i; ++j) {
			if (pts[i].first >= pts[j].first && pts[i].second >= pts[j].second) {
				kdp[i] -= 1LL * kdp[j] * calc(pts[j].first, pts[j].second, pts[i].first, pts[i].second, c) % MOD;
				if (kdp[i] < 0) {
					kdp[i] += MOD;
				}
			}
		}
	}
	printf("%d\n", kdp[(int)pts.size() - 1]);
	return 0;
}