#include<bits/stdc++.h>
using namespace std;
map<string,int>a;
int main(){
	int n;
	cin>>n;
	while(n--){
		int op,sc;
		string s;
		cin>>op;
		if(op==1){
			cin>>s>>sc;
			a.insert(pair<string,int>(s,sc));
			cout<<"OK\n";
		}else if(op==2){
			cin>>s;
			auto it=a.find(s);
			if(it==a.end()){
				cout<<"Not found\n";
			}else{
				cout<<it->second<<'\n';
			}
		}else if(op==3){
			cin>>s;
			auto it=a.find(s);
			if(it==a.end()){
				cout<<"Not found\n";
			}else{
				a.erase(it);
				cout<<"Deleted successfully\n";
			}
		}else{
			cout<<a.size()<<'\n';
		}
	}
	return 0;
}