#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;
}