using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.IO; using System.Text; class Meguru { public Meguru() { } public static int Main() { new Meguru().calc(); return 0; } Scanner cin; void calc() { cin = new Scanner(); int N = cin.nextInt(); Dictionary dic = new Dictionary(); for (int i = 0; i < N; i++) { dic[cin.next()] = true; } string[] ar1 = { "a", "a", "e", "i", "u", "u" }; string[] ar2 = { "", "b", "g", "m", "n", "r" }; do { do { StringBuilder sb = new StringBuilder(); for (int i = 0; i < 6; i++) { sb.Append(ar2[i]); sb.Append(ar1[i]); } string s = sb.ToString(); if (!dic.ContainsKey(s)) { Console.WriteLine(s); return; } } while (next_permutation(ar2)); } while (next_permutation(ar1)); Console.WriteLine("NO"); } //swap void swap(ref T a, ref T b) { T c = a; a = b; b = c; } public static bool next_permutation(T[] array) where T : IComparable { return next_permutation(array, 0, array.Length); } public static bool next_permutation(T[] array, int start, int length) where T : IComparable { int end = start + length - 1; if (end <= start) return false; int last = end; while (true) { int pos = last--; if (array[last].CompareTo(array[pos]) < 0) { int i; for (i = end + 1; array[last].CompareTo(array[--i]) >= 0; ) { } T tmp = array[last]; array[last] = array[i]; array[i] = tmp; Array.Reverse(array, pos, end - pos + 1); return true; } if (last == start) { //Array.Reverse(array, start, end - start); return false; } } } } class Scanner { string[] s; int i; char[] cs = new char[] { ' ' }; public Scanner() { s = new string[0]; i = 0; } public string next() { if (i < s.Length) return s[i++]; string st = Console.ReadLine(); while (st == "") st = Console.ReadLine(); s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries); i = 0; return next(); } public int nextInt() { return int.Parse(next()); } public long nextLong() { return long.Parse(next()); } public double nextDouble() { return double.Parse(next()); } }