#include<bits/stdc++.h>

using namespace std;

    int n, m, mx = 0;
vector<int> color, used;
vector<pair<int, int>> r;

int check(vector<int> color)
{
    int cnt = 0;
    map<pair<int, int>, int> mp;
    for(auto i : r)
    {
        if(mp.count({min(color[i.first], color[i.second]), max(color[i.first], color[i.second])}) == 0)
        {
            cnt++;
            mp[{min(color[i.first], color[i.second]), max(color[i.first], color[i.second])}] = 1;
        }
    }
    return cnt;
}

void f(int i, vector<int> color, vector<int> used)
{
    if(i == n + 1)
    {
        mx = max(check(color), mx);
        return;
    }
    for(int j = 1; j <= 6; j++)
    {
        if(used[j] == 1)
        {
            color[i] = j, used[j]++;
            f(i + 1, color, used);
        }
        else if(used[j] == 0)
        {
            color[i] = j, used[j]++;
            f(i + 1, color, used);
        }
        else if(used[j] > 1)
            continue;
    }
}

main()
{

    cin >> n >> m;
    for(int i = 0; i < m; i++)
    {
        int f, t;
        cin >> f >> t;
        r.push_back({f, t});
    }
    color.resize(n + 1, 0);
    used.resize(7, 0);
    set<int> s{1, 2, 3, 4, 5, 6, 7};
    f(1, color, used);
    cout << mx;
}