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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	P := map[int]int{}
	P[readInt()] = 1
	P[readInt()] = 1
	Loop(1, 4, func(i int) {
		if _, Exists := P[i]; !Exists {
			fmt.Println(i)
			os.Exit(0)
		}
	})
}

/////////////////////////////////////////
var scanner = bufio.NewScanner(os.Stdin)

func init() {
	//scanner.Split(bufio.ScanWords)
	scanner.Split(bufio.ScanLines)
}

func readString() string {
	scanner.Scan()
	return scanner.Text()
}

func readInt() int {
	scanner.Scan()
	t, _ := strconv.Atoi(scanner.Text())
	return t
}

func Loop(start, end int, f func(i int)) {
	for i := start; i < end; i++ {
		f(i)
	}
}