40分求看，悬关！！！

#include <iostream>
#include <cstdio>
#include <string>
#include <unordered_map>
using namespace std;
int n,len;
bool vis[1001];
string x,a[1001],y,z;
unordered_map<string,int> m;
int main(){
	cin>>n;
	while(n--){
		cin>>x;
		if(x[0]=='t'){
			cin>>y;
			if(m[y]) continue;
			a[++len]=y;
			m[y]=len;
		}
		else if(x[0]=='r'){
			if(x[1]=='m'){
				cin>>y;
				if(m[y])
				vis[m[y]]=1;
			}
			else{
				cin>>y>>z;
				if(m[y]&&!m[z])
				a[m[y]]=z;
			}
		}
		else{
			for(int i=1;i<=len;i++){
				if(!vis[i]) cout<<a[i]<<endl;
			}
		}
	}
	
	
	return 0;
}