#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define pb push_back
#define ln '\n'
//#define int long long
template <class _T>
bool chmin(_T &x, const _T &y){
bool flag = false;
if ( x > y ){
x = y; flag |= true;
}
return flag;
}
template <class _T>
bool chmax(_T &x, const _T &y){
bool flag = false;
if ( x < y ){
x = y; flag |= true;
}
return flag;
}
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
vector <int> g[n], d(n, -1), tin(n), tout(n);
for ( int i = 0; i + 1 < n; i++ ){
g[u[i]].pb(v[i]);
g[v[i]].pb(u[i]);
}
int timer = 1;
function <void(int)> dfs = [&](int x){
tin[x] = timer++;
for ( auto to: g[x] ){
if ( d[to] == -1 ){
d[to] = d[x] + 1;
dfs(to);
}
}
tout[x] = timer++;
};
d[0] = 1;
dfs(0);
vector <int> ans(n);
for ( int i = 0; i < n; i++ ){
ans[i] = d[i] & 1 ? tin[i] : tout[i];
}
return ans;
}
int find_next_station(int s, int t, vector<int> c) {
int n = (int)c.size();
if ( c[0] > s ){ // tin
int tin = s, tout = s != 1 ? c[n - 2] + 1 : c[n - 1] + 1;
if ( tin < t and tout > t ){
for ( auto &x: c ){
if ( x > t ){
return x;
}
} assert(false);
} else{
return c[n - 1];
}
} else{
int tin = c[0] + 1, tout = s;
if ( tin < t and tout > t ){
for ( int i = n - 2; i >= 0; i-- ){
if ( c[i] < t ){
return c[i];
}
} assert(false);
} else{
return tin - 1;
}
}
return -1;
}
