#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 100;
const int M = 4e5 + 100;
int n, m;
int dfn[N], low[N], clk;
int h[N], nxt[M], to[M], idx = 1;
int b[M];
int dcc[N];
void add(int u, int v){
	nxt[++idx] = h[u];to[idx] = v;h[u] = idx;
	nxt[++idx] = h[v];to[idx] = u;h[v] = idx;
} 
void tarjan(int u, int fa){
	dfn[u] = low[u] = ++clk;
	for(int i = h[u];i;i = nxt[i]){
		int v = to[i];
        if(v == fa) continue;
		if(!dfn[v]){
			tarjan(v, u);
			low[u] = min(low[u], low[v]);
			if(low[v] > dfn[u]) b[i] = b[i ^ 1] = 1;
		}		
		else low[u] = min(low[u], dfn[v]);
	}
}
int cnt, sum;
void dfs(int u){
	dcc[u] = cnt;sum++;
	for(int i = h[u];i;i = nxt[i]){
		int v = to[i];
		if(!dcc[v] && !b[i]) dfs(v);
	} 
}
int res;
int main(){	 
	scanf("%d%d",&n,&m);
	for(int i = 1;i <= m;i++){
		int u, v;
		scanf("%d%d",&u,&v); 
		add(u, v);	
	}
	for(int i = 1;i <= n;i++) if(!dfn[i]) tarjan(i, 0);
	for(int i = 1;i <= n;i++) if(!dcc[i]){
		++cnt; 
        sum = 0;
		dfs(i);
        res = max(res, sum);
	}
    printf("%d\n",res);
	return 0;
}