#include<iostream>
#include<cstring>
#include<stack>
#include<vector>
using namespace std;

const int N = 2e6 + 5;

struct edge{
    int to, next;
}e[N << 1];
int head[N], cnt;
void add(int u, int v){
    e[cnt] = {v, head[u]};
    head[u] = cnt++;
}

vector<int>ans[N];
int dcc_cnt;

int bridge[N << 1];

int dfn[N], low[N], num;
int dcc[N], siz[N];
stack<int>s;
void tarjan(int u, int from){
    dfn[u] = low[u] = ++num;
    s.push(u);
    for(int i = head[u]; ~i; i = e[i].next){
        int v = e[i].to;
        if(!dfn[v]){
            tarjan(v, i);
            low[u] = min(low[u], low[v]);
            if(low[v] > dfn[u]) bridge[i] = bridge[i ^ 1] = 1;
        }else if(i != (from ^ 1)) low[u] = min(low[u], dfn[v]);
    }

    if(dfn[u] == low[u]){
        dcc_cnt++;
        int v;
        do{
            v = s.top();
            s.pop();
            dcc[v] = dcc_cnt;
            siz[dcc_cnt]++;
        }while(u != v);
    }
}

void solve(){
    memset(head, -1, sizeof(head));
    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= m; i++){
        int u, v;
        cin >> u >> v;
        add(u, v);
        add(v, u);
    }
    for(int i = 1; i <= n; i++){
        if(!dfn[i]) tarjan(i, -1);
    }
    int maxn = 0;
    for(int i = 1; i <= dcc_cnt; i++){
        maxn = max(maxn, siz[i]);
    }
    cout << maxn << '\n';
}

int main(){
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}