using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{

    public static void Main(string[] args)
    {
        var input = new List<string[]>();
        int count = int.Parse(Console.ReadLine());
        for (int i = 0; i < count; i++) {
            input.Add(Console.ReadLine().Split(' '));
        }

        var candidates = new List<string>() { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
        for (int i = 0; i < input.Count; i++)
        {
            if (input[i][4] == "YES")
            {
                var targets = new List<string>();
                foreach (string candidate in candidates)
                {
                    if (!input[i].Contains(candidate))
                    {
                        targets.Add(candidate);
                    }
                }
                foreach (string target in targets)
                {
                    candidates.Remove(target);
                }
            }
            else
            {
                for (int j = 0; j < 4; j++)
                {
                    candidates.Remove(input[i][j]);
                }
            }
        }

        Console.WriteLine(candidates[0]);
    }
}