#include <iostream>

 #include <cstdio>

 #include <bitset>

 using namespace std;

 const int maxn = ;

 int n, m;

 bitset<maxn> maps[maxn];

 void floyd() {

     for (int k = ; k <= n; k++) {

         for (int i = ; i <= n; i++) {

             if (maps[i][k]) maps[i] |= maps[k];

         }

     }

 }

 int main() {

     scanf("%d%d",&n,&m);

     for (int i = ; i <= m; i++) {

         int u, v; scanf("%d%d",&u,&v);

         maps[u][v] = true;

     }

     floyd();

     int ans = ;

     for (int i = ; i <= n; i++) {

         for (int j = i+; j <= n; j++) {

             if (!maps[i][j] && !maps[j][i]) ans++;

         }

     }

     printf("%d\n",ans);

     return ;

 }