#include <bits/stdc++.h>
// #include "traffic.h"
using namespace std;
const int MAXN = 1e6;
vector<vector<int>> g;
int sub[MAXN], m[MAXN]={}, sum = 0;
pair<int, int> ans = {(int)1e18, -1};
int dfs0(int u, int par){
for(int v : g[u]) if(v != par){
sub[u] += dfs0(v, u);
m[u] = max(m[u], sub[v]);
}
return sub[u];
}
int LocateCentre(int n, int pop[], int S[], int D[]){
for(int i=0; i<n; ++i) sum += (sub[i] = pop[i]);
g.resize(n);
for(int i=0; i<n-1; ++i){
g[S[i]].push_back(D[i]);
g[D[i]].push_back(S[i]);
}
dfs0(0, 0);
for(int u=0; u<n; ++u){
m[u] = max(m[u], sum - sub[u]);
ans = min(ans, {m[u], u});
}
return ans.second;
}
