/*
  Task: I. Kevin and Grid
  Link: http://codeforces.com/contest/1392/problem/I
  Lang: cpp17
*/
#include <bits/stdc++.h>
using namespace std;

#define eb emplace_back
#define pb push_back
#define INF LLONG_MAX
#define FLT_INF pow(10.0, 16)


using ll = long long;
using vll = vector<ll>;
using ull = unsigned long long;
using int2 = pair<ll, ll>;
using int3 = tuple<ll, ll, ll>;

template <typename A> string to_string(const A& v);
string to_string(const string& s) { return '"'+ s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }

template <typename A, typename B> string to_string(const pair<A, B>& p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C> string to_string(const tuple<A, B, C>& p) {
  return "(" + to_string(std::get<0>(p)) + ", " + to_string(std::get<1>(p)) +  ", " + to_string(std::get<2>(p)) + ")";
}

template <typename A> string to_string(const A& v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename T>
void sort(vector<T>& val) {
  sort(val.begin(), val.end());
}

template <typename T>
void reverse(vector<T>& val) {
  reverse(val.begin(), val.end());
}

template <typename T>
void sort_b(vector<T>& val) {
  sort(val.begin(), val.end(), greater<T>());
}

template <typename T>
T pair_sum(pair<T, T>& val) {
  return val.first + val.second;
}


template <typename T>
T min(T a, T b, T c) {
  return min(min(a, b), c);
}

template <typename T>
T max(T a, T b, T c) {
  return max(max(a, b), c);
}


template <typename T>
T mul_mod(T a, T b, T mod) {
  T res = 0;
  a %= mod;
  while (b) {
    if (b & 1) {
      res = (res + a) % mod;
    }
    a = (2 * a) % mod;
    b >>= 1;
  }
  return res;
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...);
#endif

#define COMMON_MOD pow(10, 9) + 7
#define PI 3.14159265

// sort(a.begin(), a.end(), less<ll>()); greater<ll>()
// cout<<fixed<<setprecision(20)<<(s/kl)*2;
/* printf("%lld %lld \n", cur_n, m / 2 + 1);
sort(a.begin(), a.end(), [ ](ll& lhs, ll& rhs) {return abs(lhs) < abs(rhs);});
*/


class mytask {
public:

  mytask() { }

  
  int solve() {

    ll n, m;
    cin >> n >> m;

    vector<vll> g(n+1);
    for (ll i = 0; i < m; i++) {
      ll a, b;
      cin >> a >> b;
      g[a].pb(b);      
      g[b].pb(a);      
    }

    set<ll> seen_vertex;
    ll res = 1;
    for (ll i = 1; i <= n; i++) {
      if (seen_vertex.find(i) == seen_vertex.end()) {
        set<ll> seet_vertex_sub;
        vll current_vertex = {i};
        vll next_vertex =  {};
        while (current_vertex.size()) {
          ll v =  current_vertex.back();
          current_vertex.pop_back();
          seen_vertex.insert(v);
          seet_vertex_sub.insert(v);
          for (ll child: g[v]) {
            if (seet_vertex_sub.find(child) == seet_vertex_sub.end()) {
              seet_vertex_sub.insert(child);
              seen_vertex.insert(child);
              next_vertex.pb(child);
            }
          }
          if (current_vertex.size() == 0) {
            current_vertex = next_vertex;
            next_vertex = {};
          }
        }
        res = max(res, static_cast<ll>(seet_vertex_sub.size()));       
      }
    }

    cout << res;


    
    return 0;
  }

   

};


int main() {

  ios::sync_with_stdio(false);
  cin.tie(0);

  auto task = mytask();
  task.solve();


  //cout << endl;

  return 0;
}


Measured memory_bytes: 35756