#include<bits/stdc++.h>
#define io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
int n;
struct stu {
	string name;
	int score;
};
vector<stu> studentt;
map<string, pair<bool, int>> f;
int countt = 0;
int main() {
	io
	cin >> n;
	while (n--) {
		int x;
		cin >> x;
		string s;
		if (x != 4) cin >> s;
		if (x == 1) {
			countt++;
			int u;
			cin >> u;
			if (f[s].first)
				studentt[f[s].second].score = u;
			else {
				f[s].first = 1;
				f[s].second = studentt.size();
				studentt.push_back({s, u});
			}
			cout << "OK";
		} else if (x == 2) {
			if (f[s].first) cout << studentt[f[s].second].score;
			else cout << "Not found";
		} else if (x == 3) {
			if (f[s].first) {
				countt--;
				f[s].first = 0;
				cout << "Deleted successfully";
			} else cout << "Not found";
		} else cout << countt;
		cout << "\n";
	}
	return 0;
}