//#pragma GCC optimize("Ofast", "unroll-loops", "omit-frame-pointer","inline")
//#pragma GCC option("arch=native","tune=native","no-zero-upper")
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

#define X first
#define Y second


const ll mod = 1000000007;
//const ll mod = 998244353;



ll pew(ll a, ll b) {
    ll res = 1;
    while (b>0) {
        if (b&1) res = res*a%mod;
        b >>= 1;
        a = a*a%mod;
    }
    return res;
}




const int N = 111;
vector<int> g[N];
ll dp[N][1<<16][2];
int curmsk[N];
vector<int> was;
vector<pair<int,int>> E;
int k, k2;

void dfs(ll u, ll p) {
    was[u] = 1;
    for (ll v: g[u]) {
        if (v==p) continue;
        if (was[v]==1 and u<v) E.push_back({u,v});
        if (was[v]==0) {
            dfs(v,u);
        }
    }
}

void dfs2(ll u, ll p) {
    was[u] = 1;
    curmsk[u] = 0;
    for (int i=0;i<E.size();i++) {
        if (E[i].X==u or E[i].Y==u) curmsk[u] += (1<<i);
    }
    for (int i=0;i<(1<<k);i++) {
        dp[u][i][0] = dp[u][i][1] = -mod;
    }
    dp[u][0][0] = 0, dp[u][curmsk[u]][1] = 1;
    for (ll v: g[u]) {
        if (v==p) continue;
        if (was[v]==0) {
            dfs2(v,u);
            vector<vector<ll>> nxt(k2,vector<ll>(2,-mod));
            int m1 = curmsk[v];
            int m0 = curmsk[u];
            int nxtmsk = m0^m1;
            for (int l=m0;l>=0;l=(l-1)&m0) {
                int m2 = m1&((1LL<<k)-1-l);
                for (int r=m2;r>=0;r=(r-1)&m2) {
                    for (int b=0;b<2;b++) {
                        for (int b2=0;b2+b<2;b2++) {
                            nxt[(l|r)&nxtmsk][b] = max(nxt[(l|r)&nxtmsk][b],dp[u][l][b]+dp[v][r][b2]);
                        }
                    }
                    if (r==0) break;
                }
                if (l==0) break;
            }
            for (int i=0;i<k2;i++) {
                dp[u][i][0] = nxt[i][0];
                dp[u][i][1] = nxt[i][1];
            }
            curmsk[u] = nxtmsk;
        }
    }
}

void solve() {
    ll n, m;
    cin >> n >> m;
    for (ll i=0;i<m;i++) {
        ll u, v;
        cin >> u >> v;
        u--, v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    was.resize(n);
    dfs(0,-1);
    sort(E.begin(),E.end());
    E.resize(unique(E.begin(),E.end())-E.begin());
    k = E.size();
    k2 = (1<<k);
    for (ll i=0;i<n;i++) was[i] = 0;
    dfs2(0,-1);
    cout << max(dp[0][0][0],dp[0][0][1]) << endl;
}

int main() {
    ios_base::sync_with_stdio(false);
    int T = 1;
    //cin >> T;
    while (T--) solve();
    return 0;
}