//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")
#ifdef LOCAL
#include <iostream>
#include <cmath>
#include <algorithm>
#include <stdio.h>
#include <cstdint>
#include <cstring>
#include <string>
#include <cstdlib>
#include <vector>
#include <bitset>
#include <map>
#include <queue>
#include <ctime>
#include <stack>
#include <set>
#include <list>
#include <random>
#include <deque>
#include <functional>
#include <iomanip>
#include <sstream>
#include <fstream>
#include <complex>
#include <numeric>
#include <cassert>
#include <array>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <thread>
#else
#include <bits/stdc++.h>
#endif

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

template<typename T>
inline bool umin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

//template<typename T>
//inline bool umax(T &a, T b) {
//    if (a < b) {
//        a = b;
//        return true;
//    }
//    return false;
//}
template<typename T, typename T1>
inline bool umax(T &a, T1 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#ifdef LOCAL
#define D for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template <class ...Ts> auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define D while (false)
#define LOG(...)
#endif // LOCAL

const int max_n = 111, inf = 1000111222;

set <pii> edges;
vector <pii> bad;
vector <int> edge[max_n];

bool used[max_n] = {};

inline void dfs (int v) {
    used[v] = true;
    for (int to : edge[v]) {
        if (!used[to]) {
            dfs(to);
            edges.insert({v, to});
            edges.insert({to, v});
        }
    }
}

int e_mask[max_n] = {};

using base = char;

base dp[max_n][1 << 16][2] = {};
int k;
int was[max_n] = {};

inline void dfs_solve (int v, int p = -1) {
    dp[v][e_mask[v]][1] = 1;
    if (e_mask[v]) {
        was[v] = 1;
    }
    bool ok = !was[v];
    for (int to : edge[v]) {
        if (to == p) {
            continue;
        }
        dfs_solve(to, v);
        was[v] |= was[to];
        if (!was[to] || ok) {
            ok = false;
            for (int mask = (1 << k) - 1; mask >= 0; mask--) {
                dp[v][mask][0] += max(dp[to][0][1], dp[to][0][0]);
                dp[v][mask][1] += dp[to][0][0];
                if (mask) {
                    umax(dp[v][mask][0], dp[v][0][0] + dp[to][mask][1]);
                    umax(dp[v][mask][0], dp[v][0][0] + dp[to][mask][0]);
                    umax(dp[v][mask][1], dp[v][0][1] + dp[to][mask][0]);
                }
            }
            continue;
        }
        for (int mask = (1 << k) - 1; mask >= 0; mask--) {
            dp[v][mask][0] += max(dp[to][0][1], dp[to][0][0]);
            dp[v][mask][1] += dp[to][0][0];
            if (mask) {
                umax(dp[v][mask][0], dp[v][0][0] + dp[to][mask][1]);
                umax(dp[v][mask][0], dp[v][0][0] + dp[to][mask][0]);
                umax(dp[v][mask][1], dp[v][0][1] + dp[to][mask][0]);
            }
            for (int submask = mask & (mask - 1); submask; submask = (mask & (submask - 1))) {
                umax(dp[v][mask][0], dp[v][submask][0] + dp[to][mask ^ submask][1]);
                umax(dp[v][mask][0], dp[v][submask][0] + dp[to][mask ^ submask][0]);
                umax(dp[v][mask][1], dp[v][submask][1] + dp[to][mask ^ submask][0]);
            }

        }
    }
}


const int debug = 0;

mt19937 rng(228);
template<typename T = int>
inline T randll(T l = INT_MIN, T r = INT_MAX) {
    return uniform_int_distribution<T>(l, r)(rng);
}

inline ld randld(ld l = INT_MIN, ld r = INT_MAX) {
    return uniform_real_distribution<ld>(l, r)(rng);
}

int main() {
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;
    vector <pii> e(m);
    for (int i = 0, a, b; i < m; i++) {
        if (debug) {
            if (i < n - 1) {
                a = i, b = i + 1;
            }
            else {
                while (true) {
                    a = randll(0, n - 1);
                    b = randll(0, n - 1);
                    bool ok = a != b;
                    for (int j = 0; j < i; j++) {
                        if (e[j] == make_pair(a, b) || e[j] == make_pair(b, a)) {
                            ok = false;
                        }
                    }
                    if (ok) {
                        break;
                    }
                }
            }
        }
        else {
            cin >> a >> b;
            --a, --b;
        }
        edge[a].pb(b);
        edge[b].pb(a);
        e[i] = {a, b};
    }
    dfs(0);
    for (int i = 0; i < n; i++) {
        edge[i].clear();
    }
    for (int i = 0; i < m; i++) {
        if (edges.count(e[i])) {
            edge[e[i].first].pb(e[i].second);
            edge[e[i].second].pb(e[i].first);
            continue;
        }
        bad.pb(e[i]);
    }
    k = len(bad);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < k; j++) {
            if (bad[j].first == i || bad[j].second == i) {
                e_mask[i] |= 1 << j;
            }
        }
    }
    int root = 0;
    dfs_solve(root);
    base ans = 0;
    for (int i = 0; i < (1 << k); i++) {
        umax(ans, dp[root][i][0]);
        umax(ans, dp[root][i][1]);
    }
    cout << int(ans) << '\n';
}