package main
import "fmt"

func main() {
	var a, b int
	fmt.Scanf("%d %d", &a, &b)

	if a < b {
		fmt.Println(b - 2)
	}else {
		fmt.Println(2 * pow(10, 9) - b - 1)
	}
}

//aのb乗をします O(log b)
func pow(a int, b int) int {
	total := 1
	tmp := a
	for b > 0 {
		if b % 2 == 1 {
			total *= tmp
		}
		b /= 2
		tmp *= tmp
	}
	return total
}