#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;
const int inf = (1 << 30) - 1;
const ll infll = (1LL << 61) - 1;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
template <typename T>
using Matrix = vector<vector<T>>;
int rec(int N, int cnt, Matrix<int> &mt, vector<int> &index) {
  if (cnt == N) {
    set<pair<int, int>> st;
    for (int i = 0; i < N; i++) {
      for (int j = 0; j < i; j++) {
        if (mt[i][j] == 1)
          st.insert({min(index[i], index[j]), max(index[i], index[j])});
      }
    }
    int res = st.size();
    return res;
  }
  int res = 0;
  for (int j = 1; j <= 6; j++) {
    index[cnt] = j;
    res = max(res, rec(N, cnt + 1, mt, index));
  }
  return res;
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int N, M;
  cin >> N >> M;
  Matrix<int> mt(N, vector<int>(N));
  for (int i = 0; i < M; i++) {
    int a, b;
    cin >> a >> b;
    a--, b--;
    mt[a][b]++;
    mt[b][a]++;
  }
  vector<int> index(N);
  int ans = rec(N, 0, mt, index);
  cout << ans << "\n";
}
