#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(a) (a).begin(), (a).end()
#define replr(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define reprl(i, a, b) for (int i = int(a); i >= int(b); --i)
#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define mkp(a, b) make_pair(a, b)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<PII> VPI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<VPI> VVPI;
typedef pair<ll, ll> PLL;
typedef vector<ll> VL;
typedef vector<PLL> VPL;
typedef vector<VL> VVL;
typedef vector<VVL> VVVL;
typedef vector<VPL> VVPL;
template<class T> T setmax(T& a, T b) {if (a < b) return a = b; return a;}
template<class T> T setmin(T& a, T b) {if (a < b) return a; return a = b;}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T>
using indset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#include "stations.h"
VVI gp;
VI tin, tout;
int tc;
void dfs(int u, int p = -1) {
tin[u] = tc++;
for (int v : gp[u]) if (v != p) {
dfs(v, u);
}
tout[u] = tc-1;
}
VI label(int n, int k, VI U, VI V) {
gp = VVI(n);
rep(i, n-1) {
int u = U[i];
int v = V[i];
gp[u].pb(v);
gp[v].pb(u);
}
tc = 0;
tin = tout = VI(n);
dfs(0);
VI ret(n);
rep(i, n) ret[i] = 1000*tin[i] + tout[i];
/*for (int x : ret) cout << x << " "; cout << endl;*/
return ret;
}
bool isanc(int a, int b) {
return a/1000 <= b/1000 && b%1000 <= a%1000;
}
int find_next_station(int s, int t, VI c) {
if (c.size() == 1) return c[0];
int n = c.size();
int parent = -1;
for (int x : c) {
if (isanc(x, s)) parent = x;
else {
if (isanc(x, t)) return x;
}
}
return parent;
}
