SAFENET2 (SongLienThong)

//Thành phần song liên thông
#include <bits/stdc++.h>
#define int64_t long long
using namespace std;

const int N = 100005;

int n, m;
vector<int> graph[N];

int cnt = 0;
int Low[N], Visited[N];
stack<int> st;
int Parent[N], Last[N];
int Count = 0, Ans;

bool minimize(int &a, int b) { if(a > b) a = b; else return false; return true; }
bool maximize(int &a, int b) { if(a < b) a = b; else return false; return true; }

void visit(int u) {
   Low[u] = Visited[u] = ++cnt;

   for(int i = 0, v; v = graph[u][i]; ++i) {
      if(Visited[v])
         minimize(Low[u], Visited[v]);
      else {
         st.push(u);
         Parent[v] = u;
         visit(v);
         minimize(Low[u], Low[v]);

         if(Low[v] >= Visited[u]) {
            int Current = 0;
            Count++;
            do {
               v = st.top();
               st.pop();

               if(maximize(Last[v], Count))
                  Current++;
            } while(u != v);

            maximize(Ans, Current);
         }
      }
   }
   st.push(u);
}

int main(){
#ifdef LOCAL
   freopen("in.txt", "r", stdin);
#else
   freopen("SAFENET2.inp", "r", stdin);
   freopen("SAFENET2.out", "w", stdout);
#endif
   ios_base::sync_with_stdio(false);
   cin.tie(0); cout.tie(0);

   cin >> n >> m;
   for(int i = 1; i <= m; i++){
      int u, v; cin >> u >> v;
      graph[u].push_back(v);
      graph[v].push_back(u);
   }

   for(int i = 1; i <= n; i++)
      graph[i].push_back(0);

   for(int i = 1; i <= n; i++)
      if(!Visited[i]) visit(i);

   cout << max(Ans, 1) << '\n';

   return 0;
}