#include <bits/stdc++.h>
#define nmax 101
using namespace std;
ifstream fin("dmax.in");
ofstream fout("dmax.out");
int n,m,d[nmax],viz[nmax];
vector<int>h[nmax];
queue<int>c;
void Citire()
{
    int i,x,y;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        h[x].push_back(y);
        h[y].push_back(x);
    }
}
void BFS()
{
    int i,x,p;
    p=1;
    viz[p]=1;
    c.push(p);
    while(!c.empty())
    {
        x=c.front();
        c.pop();
        for(i=0;i<h[x].size();i++)
            if(!viz[h[x][i]])
        {
            viz[h[x][i]]=1;
            c.push(h[x][i]);
            d[h[x][i]]=d[x]+1;
        }
    }

}
int main()
{
    int i,maxim=0,poz;
    Citire();
    BFS();
    for(i=1;i<=n;i++)
        if(maxim<d[i])
        {
            maxim=d[i];
            poz=i;
        }
    fout<<poz<<" ";
    fin.close();
    fout.close();
    return 0;
}