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

public class Program
{
    public static void Main(string[] args)
    {
        var n = int.Parse(Console.ReadLine());
        var list = Enumerable.Range(0, 9 + 1).ToList();
        var numerics = new List<int>(4);
        var ans = string.Empty;
        var line = new string[5];
        for (var i = 0; i < n; i++)
        {
            line = Console.ReadLine().Split(' ');
            ans = line.Last();
            numerics = line.Take(4).Select(x => int.Parse(x)).ToList();
            list = (ans == "NO") ? list.Except(numerics).ToList() : list.Intersect(numerics).ToList();
        }
        Console.WriteLine(list.First());
    }
}