#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}


namespace po167{
struct UFtree
{
	using _F=int;
	int _n;
	std::vector<_F> wei;
	std::vector<int> q;
	int component;
	UFtree(int n):_n(n),wei(n),component(n),par(n){
		for(int i=0;i<n;i++){
			wei[i]=1,par[i]=i;
		}
	}
	void intialize(){
		for(auto x:q){
			wei[root(x)]=1;
			par[x]=x;
		}
		component=(int)par.size();
		q={};
	}
	//根っこを返す
	int root(int a){
		assert(0<=a&&a<_n);
		if(a==par[a]) return a;
		return par[a]=root(par[a]);
	}
	//trueなら1,falseなら0
	int same(int a,int b){
		assert(0<=a&&a<_n);
		assert(0<=b&&b<_n);
		if(root(a)==root(b)) return 1;
		else return 0;
	}
	_F size(int a){
		return wei[root(a)];
	}
	//a,bが違う根っこの元なら結合する,結合したらtrueを返す
	bool unite(int a,int b){
		a=root(a),b=root(b);
		if(a==b) return false;
		if(wei[a]<wei[b]) std::swap(a,b);
		par[b]=a;
		q.push_back(b);
		component--;
		return true;
	}
	private:
	std::vector<int> par;
};
}
using po167::UFtree;


void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,t) solve();
}

void solve(){
	int N,M;
    cin>>N>>M;
    int ans=0;
    UFtree T(N);
    vector<int> A(M),B(M);
    rep(i,M){
        cin>>A[i]>>B[i];
        A[i]--,B[i]--;
    }
    reverse(all(A));
    reverse(all(B));
    rep(i,M){
        if(T.same(A[i],B[i])){
            int a=T.root(A[i]);
            T.wei[a]++;
            chmax(ans,T.wei[a]);
        }else{
            int a=T.root(A[i]);
            int b=T.root(B[i]);
            T.wei[a]++;
            T.wei[b]++;
            T.unite(a,b);
            chmax(ans,T.wei[T.root(a)]);
        }
    }
    cout<<ans-1<<"\n";
}