#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
bool dbg = 0;
clock_t start_time = clock();
void bad(string mes = "Impossible") {
  cout << mes;
  exit(0);
}
void bad(int mes) {
  cout << mes;
  exit(0);
}
template <typename T>
string bin(T x, int st = 2) {
  string ans = "";
  while (x > 0) {
    ans += char('0' + x % st);
    x /= st;
  }
  reverse(ans.begin(), ans.end());
  return ans.empty() ? "0" : ans;
}
template <typename T>
void upmax(T& x, T y) {
  x = max(x, y);
}
template <typename T>
void upmin(T& x, T y) {
  x = min(x, y);
}
template <typename T>
T input() {
  T ans = 0, m = 1;
  char c = ' ';
  while (!((c >= '0' && c <= '9') || c == '-')) {
    c = getchar();
  }
  if (c == '-') m = -1, c = getchar();
  while (c >= '0' && c <= '9') {
    ans = ans * 10 + (c - '0'), c = getchar();
  }
  return ans * m;
}
template <typename T>
void read(T& a) {
  a = input<T>();
}
template <typename T>
void read(T& a, T& b) {
  read(a), read(b);
}
template <typename T>
void read(T& a, T& b, T& c) {
  read(a, b), read(c);
}
template <typename T>
void read(T& a, T& b, T& c, T& d) {
  read(a, b), read(c, d);
}
const int inf = 1e9 + 20;
const short short_inf = 3e4 + 20;
const long double eps = 1e-6;
const int maxn = (int)3e5 + 12;
const long long llinf = 2e18 + 5;
const double PI = acos(-1.0);
const int mod = 1e9 + 7;
template <typename T>
T binpow(T n, T second) {
  if (second <= 0) return 1LL;
  if (second % 2 == 0) {
    T b = binpow(n, second / 2);
    return (1LL * b * b) % mod;
  } else {
    return (1LL * binpow(n, second - 1) * n) % mod;
  }
}
vector<pair<int, int> > e;
int v[100];
int n, m;
map<pair<int, int>, int> second;
int ans;
void go(int pos) {
  if (pos == n) {
    second.clear();
    for (int i = 0; i < m; i++) {
      second[minmax(v[e[i].first], v[e[i].second])] += 1;
    }
    int cc = 0;
    for (auto [k, val] : second) {
      int a = k.first, b = k.second;
      if (a == b) {
        cc++;
      } else {
        cc += min(val, 1);
      }
    }
    upmax(ans, cc);
    return;
  }
  for (int c = 1; c <= 6; c++) {
    v[pos] = c;
    go(pos + 1);
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    int u, v;
    cin >> u >> v;
    u--, v--;
    e.push_back({u, v});
  }
  go(0);
  cout << ans << endl;
  return 0;
}
