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