Problem:
Score: 100 points

Problem Statement

Takahashi is solving quizzes. He has easily solved all but the last one.

The last quiz has three choices: 1, 2, and 3.

With his supernatural power, Takahashi has found out that the choices A and B are both wrong.

Print the correct choice for this problem.

Constraints

Each of the numbers A and B is 1, 2, or 3.

A and B are different.

Input

Input is given from Standard Input in the following format:

A
B

Output

Print the correct choice.

Sample Input 1

3
1

Sample Output 1

2

When we know 3 and 1 are both wrong, the correct choice is 2.

Sample Input 2

1
2

Sample Output 2

3

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

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

namespace AtCoder
{
	class Program
	{
		public static void Main()
		{
				var intArray = IO.ReadIntArray();
				int A = intArray[0] , B = intArray[1];
				IO.Write(6 - (A + B));
		}
	}

	public static class IO
	{
		public static string   Read()								 { return Console.ReadLine(); }
		public static string[] ReadArray(char iSplitter = ' ')		 { return Read().Split(iSplitter); }
		public static int	   ReadInt()							 { return int.Parse(Read()); }
		public static int[]	   ReadIntArray(char iSplitter = ' ')	 { return ReadArray().Select(iText => int.Parse(iText)).ToArray(); }
		public static long	   ReadLong()							 { return long.Parse(Read()); }
		public static long[]   ReadLongArray(char iSplitter = ' ')	 { return ReadArray().Select(iText => long.Parse(iText)).ToArray(); }
		public static double   ReadDouble()							 { return double.Parse(Read()); }
		public static double[] ReadDoubleArray(char iSplitter = ' ') { return ReadArray().Select(iText => double.Parse(iText)).ToArray(); }
		public static char	   ReadChar()							 { return Read()[0]; }
		public static char[]   ReadCharArray()						 { return Read().ToCharArray(); }

		public static void Write(string iValue)	 { Console.WriteLine(iValue); }
		public static void Write(int iValue)	 { Console.WriteLine(iValue); }
		public static void Write(long iValue)	 { Console.WriteLine(iValue); }
		public static void Write(double iValue)  { Console.WriteLine(iValue); }
		public static void Write(char iValue)	 { Console.WriteLine(iValue); }
		public static void Write(decimal iValue) { Console.WriteLine(iValue); }
		public static void Write(bool iValue)	 { Console.WriteLine(iValue ? "Yes" : "No"); }
		public static void Write<Type>(IEnumerable<Type> iValue , string iJoinWord = " ") { Console.WriteLine(string.Join(iJoinWord , iValue)); }
	}
}