#include <iostream>
#include <vector>
#include <utility>
using namespace std;

void mb(const vector<vector<int>>& edges,int pt,vector<int>& enter,vector<int>& leave,int lv,vector<int>&back,vector<int>&parent){
    enter[pt]=lv;
    back[pt]=pt;
    for (int x:edges[pt]){
        if (enter[x]!=-1){
            if (enter[back[pt]]>enter[x]&&x!=parent[pt]){
                back[pt]=x;
            }
        }else{
            parent[x]=pt;
        mb(edges,x,enter,leave,lv+1,back,parent);
        if (enter[back[pt]]>enter[back[x]]){
            back[pt]=back[x];
        }
        lv=leave[x];
        }
    }
    leave[pt]=lv+1;
}

pair<int,int> cutpoint(const vector<vector<int>>& edges,int pt,const vector<int>& enter,vector<int>& leave,int N,const vector<int>&back,const vector<int>& parent){
    int parts=1;
    int mindartsize=0;//inf
    int sumsize=0;
    for (int x:edges[pt]){
        if (parent[x]==pt&&enter[back[x]]>=enter[pt]){
            ++parts;
            sumsize+=(leave[x]-enter[x]+1)/2;
            mindartsize=max(mindartsize,(leave[x]-enter[x]+1)/2);
        }
    }
    if (pt==0)
        return pair<int,int>(parts-1,-mindartsize);
    mindartsize=max(mindartsize,N-sumsize-1);
    return pair<int,int>(parts,-mindartsize);
}

int main(){
    ios::sync_with_stdio(0);
    int N,M;
    cin>>N>>M;
    vector<vector<int>> edges(N);
    for (int i=0; i!=M;++i){
        int a,b;
        cin>>a>>b;
        --a;--b;
        edges[a].push_back(b);
        edges[b].push_back(a);
    }
    vector<int> enter(N,-1),leave(N,-1),back(N),parent(N);
    //for (int i=0; i!=N;++i) if (enter[i]==-1)
    mb(edges,0,enter,leave,0,back,parent);
    int rplace;
    pair<int,int> res;res.first=-N*10;
    for (int i=0; i!=N;++i){
        auto x=cutpoint(edges,i,enter,leave,N,back,parent);
        if (res<x) {res=x; rplace=i;};
    }
    cout<<rplace+1<<"\n";

}