#include <iostream>
#include <cstdio>
#include <map>
#include <string>
using namespace std;
int main()
{
	int n;
	map<string, int> system;//学籍管理系统的map
	scanf("%d", &n);
	for(int i = 1; i <= n; i++)
	{
		int zt;//状态
		string name;
		int score;
		scanf("%d", &zt);
		switch(zt)
		{
			case 1:
				cin >> name >> score;
				if(!system[name])
					system[name] = score;
				else
					system[name] = score;
				
				printf("OK\n");
				break;
			
			case 2:
				cin >> name;
				if(!system[name])
					printf("Not Found\n");
				else
					printf("%d\n", system[name]);
				break;
			
			case 3:
				cin >> name;
				if(system[name])
				{
					system.erase(name);
					printf("Deleted successfully\n");
				}
				else
					printf("Not Found\n");
				break;
			
			case 4:
				printf("%d\n", system.size());
				break;
				
		}
		
	}
	
	return 0;
}