#include <bits/stdc++.h>
using namespace std;
int n, m, ccnt = 1, cnt, ans;
int dfn[100005], low[100005], head[100005], id[100005], to[420005], nxt[420005];
bool b[420005];
vector <vector <int> > g;
inline void add(int p, int q) {
	nxt[++ccnt] = head[p];
	to[ccnt] = q;
	head[p] = ccnt;
}
void tarjan(int p, int q) {
	dfn[p] = low[p] = ++cnt;
	for (int i = head[p]; i; i = nxt[i]) {
		if (dfn[to[i]] == 0) {
			tarjan(to[i], i);
			if (dfn[p] < low[to[i]]) {
				b[i] = b[i ^ 1] = 1;
			}
			low[p] = min(low[p], low[to[i]]);
		} else if (i != (q ^ 1)) {
			low[p] = min(low[p], dfn[to[i]]);
		}
	}
}
void dfs(int p, int q) {
	id[p] = q;
	g[q - 1].push_back(p);
	for (int i = head[p]; i; i = nxt[i]) {
		if (id[to[i]] || b[i]) continue;
		dfs(to[i], q);
	}
}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	int p, q;
	for (int i = 1; i <= m; ++i) {
		cin >> p >> q;
		if (p == q) continue;
		add(p, q);
		add(q, p);
	}
	for (int i = 1; i <= n; ++i) {
		if (dfn[i] == 0) {
			tarjan(i, 0);
		}
	}
	cnt = 0;
	for (int i = 1; i <= n; ++i) {
		if (id[i] == 0) {
			g.push_back(vector <int>());
			dfs(i, ++cnt);
		}
	}
	for (int i = 0; i < cnt; i++) {
		if (g[i].size() > ans) {
			ans = g[i].size();
		}
	}
	cout << ans;
	return 0;
}