using System; using System.IO; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace AtCoder.Contest.A { static class Program { public static void Main(string[] args) { var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; Console.SetOut(sw); var cin = new Scanner(); int n = cin.NextInt(); var ok = new bool[n]; for (int i = 0; i < n; i++) { ok[i] = true; } for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { string s = cin.Next(); if (i != j && s != "nyanpass") ok[j] = false; } } if (ok.Count(x => x == true) == 1) Console.WriteLine(Array.FindIndex(ok, x => x == true) + 1); else { Console.WriteLine(-1); } Console.Out.Flush(); } } 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); if (s.Length == 0) return Next(); i = 0; return s[i++]; } public int NextInt() { return int.Parse(Next()); } public int[] ArrayInt(int N, int add = 0) { int[] Array = new int[N]; for (int i = 0; i < N; i++) { Array[i] = NextInt() + add; } return Array; } public long NextLong() { return long.Parse(Next()); } public long[] ArrayLong(int N, long add = 0) { long[] Array = new long[N]; for (int i = 0; i < N; i++) { Array[i] = NextLong() + add; } return Array; } public double NextDouble() { return double.Parse(Next()); } public double[] ArrayDouble(int N, double add = 0) { double[] Array = new double[N]; for (int i = 0; i < N; i++) { Array[i] = NextDouble() + add; } return Array; } } }