题目传送门

#include<bits/stdc++.h>
using namespace std;
vector<int> k[1000001];
string s;

int n,x,y;
int main(){
	cin>>n;
	for(int i=1;i<=100001;i++) k[i].push_back(1);
	 
	for(int i=1;i<=n;i++){
		cin>>s>>x>>y;
		if(s=="ADD"){
			k[x].push_back(y);
		}else{
			if(!(k[x].size()-1)) cout<<-1<<endl;
			else if(k[x].size()<=y) cout<<-1<<endl;
			else cout<<k[x][y]<<endl;
		}
	}
	return 0;
}