#include<bits/stdc++.h>
using namespace std;
int n,m;
struct node{
	int to,ok;
}e[2000005];int head = 1,nw =0;
vector<int>p[200005];
int low[200005],dfn[200005],col[200005],sz[200005];
void tarjan(int now,int fa){
	low[now] = dfn[now] = ++nw;
	for(int i=0;i<p[now].size();i++){
		int to = e[p[now][i]].to;
		if(!dfn[to]){
			tarjan(to,now);
			if(low[to]>dfn[now])e[p[now][i]].ok = e[p[now][i]^1].ok = 1;
			low[now] = min(low[now],low[to]);
		}else if(to!=fa){
			low[now] = min(low[now],dfn[to]);
		}
	}return;
}void dfs(int now,int c){
	sz[c]++;col[now] = c;
	for(int i =0;i<p[now].size();i++){
		int to = e[p[now][i]].to,ok = e[p[now][i]].ok;
		if(col[to] == 0 and !ok)dfs(to,c);
	}return;
}
signed main(){
	cin >> n >> m;
	for(int i = 1;i<=m;i++){
		int a,b;cin >>a  >> b;
		e[++head].to = b,p[a].push_back(head);
		e[++head].to = a,p[b].push_back(head);
	}tarjan(1,-1);
	for(int i = 1;i<=n;i++){
		if(!col[i])dfs(i,i);
	}int ans =0 ;
	for(int i = 1;i<=n;i++)ans = max(ans,sz[i]);
	cout << ans << endl;
	return 0;
}