#include <bits/stdc++.h>
using namespace std;
const int N = 8;
bool vis[N][N];
int n, m, ans, a[8];
vector<pair<int, int> > edges;
vector<int> v;
int calc() {
  memset(vis, 0, sizeof vis);
  for (auto X : edges) {
    int x = X.first;
    int y = X.second;
    vis[a[x]][a[y]] = vis[a[y]][a[x]] = 1;
  }
  int ret = 0;
  for (int i = 1; i <= 6; i++)
    for (int j = i; j <= 6; j++) ret += vis[i][j];
  return ret;
}
void bt(int i) {
  if (i == n + 1) {
    for (int i = 1; i <= n; i++) a[i] = v[i];
    ans = max(ans, calc());
    return;
  }
  for (int j = 1; j <= 6; j++) {
    v.push_back(j);
    bt(i + 1);
    v.pop_back();
  }
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    edges.push_back({a, b});
  }
  if (n <= 6) {
    printf("%d\n", m);
    return 0;
  }
  v.push_back(69);
  bt(1);
  printf("%d\n", ans);
}
