#include <bits/stdc++.h>
using namespace std;
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define ll long long
ll mod=1000000007;
int inf=1000000007;
ll infl=1000000000000000007;
const int N=1007;
vector<int>G[N];
int pre[N],post[N];
bool col[N];
int cnt;
void dfs(int v,int o)
{
if(!col[v]) cnt++;
pre[v]=cnt;
for(auto u:G[v])
{
if(u==o) continue;
col[u]=col[v]^1;
dfs(u,v);
}
if(col[v]) cnt++;
post[v]=cnt;
}
vector<int> label(int n,int k,vector<int>U,vector<int>V)
{
for(int i=0;i<n-1;i++)
{
G[U[i]].pb(V[i]);
G[V[i]].pb(U[i]);
}
dfs(0,-1);
vector<int>ans(n);
for(int i=0;i<n;i++)
{
if(col[i]==0) ans[i]=pre[i];
else ans[i]=post[i];
}
return ans;
}
int find_next_station(int s,int t,vector<int>c)
{
sort(all(c));
int o=-1;
bool color=0;
for(auto u:c) if(u<s) color=1;
if(s!=1)
{
if(color) o=c[0];
else o=c.back();
}
if(color)
{
reverse(all(c));
int R=s;
for(auto u:c)
{
if(u==o) continue;
if(u<=t&&t<=R) return u;
R=u;
}
}
else
{
int L=s;
for(auto u:c)
{
if(u==o) continue;
if(L<=t&&t<=u) return u;
L=u;
}
}
return o;
}
/*int main()
{
vector<int>c=label(5,10,{0,1,1,2},{1,2,3,4});
for(auto x:c) cout<<x<<endl;
cout<<find_next_station(c[2], c[0],{c[4],c[1]})<<endl;
cout<<find_next_station(c[1], c[3],{c[3],c[2],c[0]})<<endl;
return 0;
}*/
