#include <bits/stdc++.h>
using namespace std;
const int N = 10;
int mx = 0;
vector<int> g[N];
int n;
int col[N];
int cnt[N][N];
void gen(int v) {
  if (v == n) {
    for (int i = 0; i < n; i++)
      for (int u : g[i]) {
        int t = col[i];
        int z = col[u];
        cnt[min(t, z)][max(t, z)] = 1;
      }
    int cur = 0;
    for (int i = 0; i < 6; i++)
      for (int j = 0; j < 6; j++) {
        cur += cnt[i][j];
        cnt[i][j] = 0;
      }
    mx = max(mx, cur);
    return;
  }
  for (int i = 0; i < 6; i++) {
    col[v] = i;
    gen(v + 1);
  }
}
int solve() {
  if (!(cin >> n)) return 1;
  int m;
  cin >> m;
  for (int i = 0; i < n; i++) g[i].clear();
  for (int i = 0; i < m; i++) {
    int x, y;
    cin >> x >> y;
    x--;
    y--;
    g[x].push_back(y);
    g[y].push_back(x);
  }
  mx = 0;
  gen(0);
  cout << mx << endl;
  return 0;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int TET = 1e9;
  for (int i = 1; i <= TET; i++) {
    if (solve()) break;
    cout << '\n';
  }
}
