using System;
using System.Collections.Generic;
using System.Text;
class Program
{
    public void Proc()
    {
        Reader.IsDebug = false;
        int inptCount = int.Parse(Reader.ReadLine());
        List<int> ngList = new List<int>();
        List<int> okList = new List<int>();
        for (int i = 0; i <= 9; i++)
        {
            okList.Add(i);
        }
        for (int i = 0; i < inptCount; i++)
        {
            string[] inpt = Reader.ReadLine().Split(' ');
            if (inpt[inpt.Length - 1] == "NO")
            {
                for (int j = 0; j < inpt.Length - 1; j++)
                {
                    int num = int.Parse(inpt[j]);
                    if (!ngList.Contains(num))
                    {
                        ngList.Add(num);
                    }
                }
            }
            else
            {
                List<int> newList = new List<int>();
                for (int j = 0; j < inpt.Length - 1; j++)
                {
                    int num = int.Parse(inpt[j]);
                    if (okList.Contains(num) && (!newList.Contains(num)))
                    {
                        newList.Add(num);
                    }
                }
                okList = newList;
            }
        }
        foreach (int num in ngList)
        {
            okList.Remove(num);
        }
        Console.WriteLine(okList[0]);

    }





    public class Reader
    {
        public static bool IsDebug = true;
        private static String PlainInput = @"
 

4
2 6 5 3 NO
1 0 4 7 YES
1 7 8 4 YES
7 1 9 8 NO




 
";
        private static System.IO.StringReader Sr = null;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (Sr == null)
                {
                    Sr = new System.IO.StringReader(PlainInput.Trim());
                }
                return Sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        public static int[] GetInt(char delimiter = ' ', bool trim = false)
        {
            string inptStr = ReadLine();
            if (trim)
            {
                inptStr = inptStr.Trim();
            }
            string[] inpt = inptStr.Split(delimiter);
            int[] ret = new int[inpt.Length];
            for (int i = 0; i < inpt.Length; i++)
            {
                ret[i] = int.Parse(inpt[i]);
            }
            return ret;
        }
    }
    static void Main()
    {
        Program prg = new Program();
        prg.Proc();
    }
}