#include <iostream>#include <fstream>#include <algorithm>#include <ctime>#include <cmath>#include <cstdlib>#include <cstdio>#include <cstring>#include <vector>using namespace std;#define mmst(a, b) memset(a, b, sizeof(a))typedef long long LL;const int maxn = 105;int n, m;int vis[maxn][maxn];int main(){int i, j, k, ans, u, v;scanf("%d%d", &n, &m);while (scanf("%d%d", &u, &v) != EOF) vis[u][v] = true;ans = 0;for (i = 1; i <= n; i++){for (j = 1; j < i; j++){for (k = 1; k <= m; k++)if (vis[i][k] != vis[j][k]) break;if (k > m) break;}if (j >= i) ans++;}printf("%dn", ans);return 0;}
