Concert Tickets

1#include<bits/stdc++.h>
2using namespace std;
3#define int long long
4signed main(){
5  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
6  int n,m; cin>>n>>m;
7  map<int,int>mp;
8  while(n--){
9    int x; cin>>x;
10    ++mp[-x];
11  }
12  while(m--){
13    int x; cin>>x;
14    auto it=mp.lower_bound(-x);
15    if(it==mp.end()) cout<<"-1\n";
16    else{
17      cout<<-it->first<<'\n';
18      if(!--it->second) mp.erase(it);
19    }
20  }
21  return 0;
22}