#include <bits/stdc++.h>
#define int long long int
using namespace std;
int n;
string s;
map<string, int> m, cnt;
signed main() {
	cin.tie() -> sync_with_stdio(false);
	cin >> n;
	while (n--) {
		cin >> s;
		if (m.find(s) == m.end()) {
			m[s] = 1;
			puts("OK");
		} else
			cout << s << ++cnt[s] << '\n';
	}
	return 0;
}

评测不了！！！