#include<bits/stdc++.h>
using namespace std;
map <string,int> a;
int main( )
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int o;
		string s;
		cin>>o;
		if(o==1)
		{
			cin>>s;
			int score;
			cin>>score;
			a[s]=score;
			cout<<"OK\n";
		}
		else if(o==2)
		{
			cin>>s;
			if(a.find(s)!=a.end())
			{
				cout<<a[s]<<endl;
			}
			else
			{
				cout<<"Not found\n";
			}
		}
		else if(o==3)
		{
			cin>>s;
			if(a.find(s)!=a.end())
			{
				a.erase(s);
				cout<<"Deleted successfully\n";
			}
			else
			{
				cout<<"Not found\n";
			}
		}
		else  cout<<a.size();
	}
	return 0;
}