#include <bits/stdc++.h>
using namespace std;
map<pair<long long, long long>, long long> mp;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n, m;
  cin >> n >> m;
  for (long long i = 0; i < m; i++) {
    long long a, b;
    cin >> a >> b;
    a--;
    b--;
    mp[{a, b}] = 1;
    mp[{b, a}] = 1;
  }
  if (n < 7) {
    cout << m << endl;
  } else {
    long long ans = m;
    for (long long i = 0; i < n; i++) {
      for (long long j = 0; j < n; j++) {
        long long ctr = 0;
        for (long long k = 0; k < n; k++) {
          if (mp[{i, k}] == 1 and mp[{j, k}]) {
            ctr++;
          }
        }
        ans = min(ans, ctr);
      }
    }
    cout << m - ans << endl;
  }
}
