#include <bits/stdc++.h>
using namespace std;
#define pb push_back
vector<int> label(int n, int k, vector<int> u, vector<int> v){
int timer = 0, tin[n], tout[n];
vector<vector<int>> g(n);
for(int i = 0; i < n-1; ++i) g[u[i]].pb(v[i]), g[v[i]].pb(u[i]);
function<void(int, int)> dfs = [&](int v, int p){
tin[v] = timer;
for(int u: g[v]){
if(u != p) dfs(u, v);
}
tout[v] = timer++;
};
dfs(0, 0);
vector<int> l;
for(int i = 0; i < n; ++i) l.pb(tin[i] + tout[i] * 1000);
return l;
}
int find_next_station(int s, int t, vector<int> c){
for(int p: c){
if(p==t) return t;
}
int ti = t % 1000, to = t;
int sx = s % 1000, sy = s;
int par = -1;
for(int v: c){
int x = v % 1000, y = v;
if(x <= sx && sy <= y){
par = v;
}
else if(x <= ti && to <= y){
return v;
}
}
return par;
}
