#include "traffic.h"
#include<bits/stdc++.h>
using namespace std;
const int lim = 1e6 + 5;
vector<int>g[lim];
int n, cnt[lim];
void dfs(int s, int p = -1){
for(int& d : g[s]){
if(d != p){
dfs(d, s);
cnt[s] += cnt[d];
}
}
}
int LocateCentre(int N, int pp[], int S[], int D[]){
n = N;
for(int i = 0; i < n; i++){
cnt[i] = pp[i];
g[S[i]].push_back(D[i]);
g[D[i]].push_back(S[i]);
}
dfs(0);
int s = 0, p = -1;
while(true){
bool flag = true;
for(int& d : g[s]){
if(d != p && cnt[d] > (cnt[s] >> 1)){
p = s;
s = d;
flag = false;
break;
}
}
if(flag){
break;
}
}
return s;
}
