/* 4587 */

 #include <iostream>

 #include <vector>

 #include <algorithm>

 #include <cstdio>

 #include <cstring>

 #include <cstdlib>

 using namespace std;

 #define MAXN 5005

 vector<int> vc[MAXN];

 int dfs_clock;

 int cnt[MAXN];

 int pre[MAXN];

 int n, m, cur;

 int Tarjan(int u, int fa) {

     int i, j, k, v;

     int lowu, lowv;

     int child = ;

     lowu = pre[u] = ++dfs_clock;

     for (i=; i<vc[u].size(); ++i) {

         v = vc[u][i];

         if (v==fa || v==cur)

             continue;

         if (!pre[v]) {

             ++child;

             lowv = Tarjan(v, u);

             lowu = min(lowu, lowv);

             if (lowv >= pre[u])

                 ++cnt[u];

         } else if (pre[v] < pre[u])

             lowu = min(lowu, pre[v]);

     }

     if (fa < )

         cnt[u] = child - ;

     return lowu;

 }

 void init() {

     dfs_clock = ;

     memset(cnt, , sizeof(int)*n);

     memset(pre, , sizeof(int)*n);

 }

 int main() {

     int i, j, k;

     int ans;

     #ifndef ONLINE_JUDGE

         freopen("data.in", "r", stdin);

     #endif

     while (scanf("%d %d", &n, &m)!=EOF) {

         for (i=; i<n; ++i)

             vc[i].clear();

         while (m--) {

             scanf("%d %d", &i, &j);

             vc[i].push_back(j);

             vc[j].push_back(i);

         }

         ans = ;

         for (cur=; cur<n; ++cur) {

             init();

             k = ;

             for (i=; i<n; ++i) {

                 if (i!=cur && !pre[i]) {

                     ++k;

                     Tarjan(i, -);

                 }

             }

             for (i=; i<n; ++i)

                 if (i!=cur)

                     ans = max(ans, k+cnt[i]);

         }

         printf("%d\n", ans);

     }

     return ;

 }