#include<stdio.h>#include<string.h>#define N 1050int map[N][100],len[N];int pre[N],tc[N][N];int n,m; void tcdfs(int u,int p) { int ii; int temp; for(ii=1;ii<=len[u];ii++) { temp=map[u][ii]; if(pre[temp]) continue; pre[temp]=1; tc[p][temp]=1; tcdfs(temp,p); } } void dagtc() { int ii,jj; int num; memset(tc,0,sizeof(tc)); for(ii=1;ii<=n;ii++) { memset(pre,0,sizeof(pre)); pre[ii]=1; tcdfs(ii,ii); } for(ii=1,num=0;ii<=n;ii++) for(jj=1;jj<=n;jj++) { if(ii==jj) tc[ii][ii]=1; if(tc[ii][jj]) num++; } printf("%dn",num); } int main() { int ii; int a,b,temp; while(scanf("%d %d",&n,&m)!=EOF) { memset(len,0,sizeof(len)); for(ii=1;ii<=m;ii++) { scanf("%d %d",&a,&b); a++,b++; len[a]++; map[a][len[a]]=b; } dagtc(); }return 1;}
