#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#include<vector>using namespace std;#define MAXN 1010vector<vector<int> >G_from;vector<vector<int> >G_to;bool map[MAXN][MAXN];int main(){ int n,m,u,v,ans; while(~scanf("%d%d",&n,&m)){ G_from.clear();G_from.resize(n+2); G_to.clear();G_to.resize(n+2); memset(map,false,sizeof(map)); while(m--){ scanf("%d%d",&u,&v); map[u][v]=true; G_from[v].push_back(u); G_to[u].push_back(v); } ans=0; for(int k=1;k<=n;k++){ for(int i=0;i<G_from[k].size();i++){ for(int j=0;j<G_to[k].size();j++){ u=G_from[k][i],v=G_to[k][j]; if(!map[u][v]){ map[u][v]=true; G_from[v].push_back(u); G_to[u].push_back(v); } } } } for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++)if(i!=j){ if(map[i][j])ans++; } } printf("%dn",n*(n-1)/2-ans); } return 0;}
