package main

import (
	"fmt"
)

func lastDigit(s string) int {
	return int(s[len(s)-1] - '0')
}

func solve() int {
	var N, M string
	fmt.Scan(&N, &M)
	if M == "0" {
		return 1
	}
	n, m := lastDigit(N), lastDigit(M)
	if m == 0 {
		m += 10
	}
	switch n {
	case 0:
		return 0
	case 1:
		return 1
	case 2:
		switch m {
		case 1:
			return 2
		case 2:
			return 4
		default:
			return 6
		}
	case 3:
		if m == 1 {
			return 3
		}
		if m%2 == 0 {
			return 9
		}
		return 1
	case 4:
		if m == 1 {
			return 4
		}
		return 6
	case 5:
		return 5
	case 6:
		return 6
	case 7:
		if m == 1 {
			return 7
		}
		if m%2 == 0 {
			return 9
		}
		return 1
	case 8:
		switch m {
		case 1:
			return 8
		case 2:
			return 4
		default:
			return 6
		}
	case 9:
		if m%2 == 1 {
			return 9
		}
		return 1
	}
	return -1
}

func main() {
	fmt.Println(solve())
}