#include <bits/stdc++.h>
using namespace std;
struct unionfind{
  vector<int> a;
  vector<int> p;
  unionfind(int N): a(N, 0), p(N, -1){
  }
  int root(int x){
    if (p[x] == -1){
      return x;
    } else {
      p[x] = root(p[x]);
      return p[x];
    }
  }
  void unite(int x, int y){
    x = root(x);
    y = root(y);
    if (x != y){
      p[y] = x;
      a[x] = max(a[x], a[y]);
    }
    a[x]++;
  }
};
int main(){
  int N, M;
  cin >> N >> M;
  vector<int> u(M), v(M);
  for (int i = 0; i < M; i++){
    cin >> u[i] >> v[i];
    u[i]--;
    v[i]--;
  }
  unionfind UF(N);
  for (int i = M - 1; i >= 0; i--){
    UF.unite(u[i], v[i]);
  }
  int ans = 0;
  for (int i = 0; i < N; i++){
    ans = max(ans, UF.a[i]);
  }
  cout << ans << endl;
}