package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
)

func main() {
	in := bufio.NewReader(os.Stdin)
	var H, A, val int
	ans := 0

	fmt.Fscan(in, &H, &A)
	for H > 0 {
		H /= A

		val++
	}
	for i := 0; i < val; i++ {
		ans += int(math.Pow(2, float64(i)))
	}

	fmt.Println(ans)
}