lib C fun strtoll(s : UInt8*, p : UInt8**, b : Int32) : Int64 end class String def to_i64 C.strtoll(self, nil, 10) end end vowel, cons = "iaaeuu", "nbmgr" size = vowel.size + cons.size strings = [] of String (0...6).each { |vowel_pos| f = [0, 1] * 5 f.insert({0, vowel_pos * 2 - 1}.max, 1) vowel.chars.each_permutation { |v| cons.chars.each_permutation { |c| v_i, c_i = -1, -1 strings << (0...size).map { |i| if f[i] == 0 c_i += 1 cons[c_i] else v_i += 1 vowel[v_i] end }.join } } } n = read_line.to_i s = (1..n).map { read_line }.to_set puts strings.find { |str| !s.includes?(str) } || "NO"