trener

#include <iostream>

using namespace std;

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin >> n;
	int counts[26];
	for (int i = 0; i < 26; ++i) counts[i] = 0;
	bool possible = 0;
	for (int i = 0; i < n; ++i) {
		string s;
		cin >> s;
		if (++counts[s.front() - 'a'] >= 5) possible = 1;
	}
	if (possible) {
		for (int i = 0; i < 26; ++i) {
			if (counts[i] >= 5) cout << string(1, 'a'+i);
		}
	} else {
		cout << "PREDAJA";
	}
	cout << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED