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

namespace StudyApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int turn = int.Parse(Console.ReadLine());
            var possible_nums = new List<string> { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };

            for (int i = 0; i < turn; i++)
            {
                string[] inputs = Console.ReadLine().Split(' ');

                if (inputs[4].Equals("NO"))
                {
                    possible_nums.RemoveAll(num => inputs.Contains(num));
                }
                else
                {
                    possible_nums.RemoveAll(num => !inputs.Contains(num));
                }
            }

            Console.WriteLine(possible_nums.First());
        }
    }
}