传递闭包。。。不知道有没有更好的解法。。。
#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 305
#define maxm 10005
#define eps 1e-10
#define mod 998244353
#define INF 999999999
#define lowbit(x) (x&(-x))
#define mp mark_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid
#define rson o<<1 | 1, mid+1, R
typedef long long LL;
//typedef int LL;
using namespace std;
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}
// head
int mat[maxn][maxn];
int n, m;
void init(void)
{
memset(mat, 0, sizeof mat);
}
void work(int _)
{
int ans = 0, a, b;
for(int i = 1; i <= n; i++) mat[i][i] = 1;
while(m--) {
//scanf("%d%d", &a, &b);
scanf(a), scanf(b);
if(mat[b][a]) ans++;
else if(!mat[a][b]){
mat[a][b] = 1;
for(int i = 1; i <= n; i++)
if(mat[i][a])
for(int j = 1; j <= n; j++)
if(mat[b][j])
mat[i][j] = 1;
}
}
printf("%d. %d\n", _, ans);
}
int main(void)
{
int _ = 0;
while(scanf("%d%d", &n, &m), n!=0 || m!=0) {
init();
work(++_);
}
return 0;
}
