#include <bits/stdc++.h>

using namespace std;

vector< vector<int> > graph;
vector<int> fup;
vector<int> tin;
vector<int> used;
int timer = 0;
vector<int> max_component_size;
vector<int> rest;

int dfs(int v, int parent=-1) {
    used[v] = true;
    fup[v] = tin[v] = timer++;
    int component_size = 1;
    for (int u: graph[v]) {
        if (u != parent) {
            if (used[u]) {
                fup[v] = min(fup[v], tin[u]);
            } else {
                int size_u = dfs(u, v);
                fup[v] = min(fup[v], fup[u]);
                component_size += size_u;
                if (fup[u] >= tin[v]) {
                    max_component_size[v] = max(max_component_size[v], size_u);
                    rest[v] -= size_u;
                }
            }
        }
    }
    return component_size;
}

int main() {
    ios_base::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;

    used.assign(n, false);
    graph.assign(n, vector<int>());
    fup.assign(n, -1);
    tin.assign(n, -1);
    max_component_size.assign(n, 0);
    rest.assign(n, n - 1);

    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    dfs(0);

    int dragon = 0;
    int max_number = n;
    for (int i = 0; i < n; i++) {
        int number = max(max_component_size[i], rest[i]);
        if (number < max_number) {
            max_number = number;
            dragon = i;
        }
    }

    cout << dragon + 1 << endl;
}