#include "stations.h"
#include<bits/stdc++.h>
using namespace std;
typedef long double ld;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=1e3+7;
int pre[LIM], post[LIM], lpre, lpost;
vector<int>V[LIM];
void DFS(int x, int o) {
++lpre;
pre[x]=lpre;
for(auto i : V[x]) if(i!=o) DFS(i, x);
++lpost;
post[x]=lpost;
}
vector<int>label(int n, int k, vector<int>u, vector<int>v) {
vector<int>ans(n);
rep(i, n-1) {
V[u[i]].pb(v[i]);
V[v[i]].pb(u[i]);
}
DFS(0, 0);
rep(i, n) ans[i]=i;
return ans;
}
int find_next_station(int s, int t, vector<int>c) {
int ojciec=-1;
for(auto i : c) if(pre[i]<pre[s]) ojciec=i;
for(auto i : c) if(i!=ojciec && pre[i]<=pre[t] && post[i]>=post[t]) return i;
return ojciec;
}
