#include <cstdio>
#include <algorithm>

const int M = 128;
int main(){
	int N, E, Map[M][M], i, j, t, k;
	scanf("%d", &t );
	while( t-- ){
		scanf("%d %d", &N, &E );
		memset( Map, 0, sizeof(Map) );
		int src, des;
		for( i = 0; i < E; i++ ){
			scanf("%d %d", &src, &des );
			Map[src][des] = 1;
		}
		for( k = 1; k <= N; k++ ){
			for( i = 1; i <= N; i++ ){
				for( j = 1; j <= N; j++ ){	
					Map[i][j] += Map[i][k]*Map[k][j];
					if(Map[i][j])
						Map[i][j]=1;
				}
			}
		}
		int count = 0;
		for( i = 1; i <= N; i++ ){
			int x = 0;
			for( j = 1; j <= N; j++ ){
				if( Map[i][j])
					x++;
			}
			int y = 0;
			for( j = 1; j <= N; j++ ){
				if( Map[j][i])
					y++;
			}
			if( ((x+1) > (N+1)/2) || ((y+1) > (N+1)/2) ){
				count++;
			}
		}
		printf("%d\n", count );
	}
	return 0;
}