#include <bits/stdc++.h>
// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <cmath>
#include <iomanip>
#include <time.h>
#define dibs reserve
#define OVER9000 1234567890
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define tisic 47
#define soclose 1e-8
#define chocolate win
// so much chocolate
#define patkan 9
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):x)
#define uint unsigned int
#define dbl long double
#define pi 3.14159265358979323846
using namespace std;
// mylittledoge

#ifdef DONLINE_JUDGE
	// palindromic tree is better than splay tree!
	#define lld I64d
#endif

int main() {
	cin.sync_with_stdio(0);
	cin.tie(0);
	cout << fixed << setprecision(10);
	int T;
	scanf(" %d",&T);
	for(int t =0; t < T; t++) {
		int N,M;
		scanf(" %d %d",&N,&M);
		int n =2*N+2;
		vector< vector<int> > F(n,vector<int>(n,0));
		for(int i =0; i < N; i++) F[0][i+1] =F[N+i+1][n-1] =1;
		for(int i =0; i < M; i++) {
			int a,b;
			scanf(" %d %d",&a,&b);
			if(a != b) F[a][N+b] =1;}
		int f =0;
		while(true) {
			queue<int> q;
			vector<int> ako(n,-1);
			q.push(0);
			ako[0] =0;
			while(!q.empty()) {
				for(int i =0; i < n; i++) if(F[q.front()][i] > 0 && ako[i] == -1) {
					ako[i] =q.front();
					q.push(i);}
				q.pop();}
			if(ako[n-1] == -1) break;
			f++;
			int akt =n-1;
			while(akt > 0) {
				F[ako[akt]][akt]--;
				F[akt][ako[akt]]++;
				akt =ako[akt];}
			}
		printf("%d\n",N-f);}
	return 0;}

// look at my code
// my code is amazing