#include<bits/stdc++.h>
#include<atcoder/all>
#include"testlib.h"
using namespace std;
using ll = long long;

const ll Nmin = 2, Nmax = 200'000;

int main(){
    registerValidation();
    ll n = inf.readLong(Nmin,Nmax);
    inf.readEoln();
    atcoder::dsu d(n);
    for (int i = 0; i < n-1; i++){
        ll u = inf.readLong(1LL,n);
        inf.readSpace();
        ll v = inf.readLong(1LL,n);
        inf.readEoln();
        u--, v--;
        ensure(!d.same(u,v));
        d.merge(u,v);
    }
    inf.readEof();
}