import java.util.*; public class Main { static HashSet set; static boolean is_vowel(char a) { if (a == 'a' || a == 'i' || a == 'u' || a == 'e' || a == 'o') return true; return false; } static char[] moji = {'i', 'n', 'a', 'b', 'a', 'm', 'e', 'g', 'u', 'r', 'u'};//11moji static void func(char[] now, int current, int used) { if (current == 11) { if (!set.contains(new String(now))) { System.out.println(now); System.exit(0); } else { return; } } for (int i = 0; i < 11; i++) { if ((used >> i & 1) == 0) { // if (((used >> 2 & 1) == 0 && (used >> 4 & 1) > 0) || ((used >> 8 & 1) == 0 && (used >> 10 & 1) > 0)) // return; if ((used >> 0 & 1) > 0 && (used >> 2 & 1) > 0 && (used >> 4 & 1) > 0 && (used >> 6 & 1) > 0 && (used >> 8 & 1) > 0 && (used >> 10 & 1) > 0) return; now[current] = moji[i]; if (current > 0) { if (!is_vowel(now[current - 1]) && !is_vowel(now[current])) { continue; } } used += 1 << i; func(now, current + 1, used); used -= 1 << i; } } } public static void main(String[] args) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); set = new HashSet<>(); for (int i = 0; i < N; i++) set.add(sc.next()); func(new char[11], 0, 0); System.out.println("NO"); } }