import sys
import logging
import math
input = sys.stdin.readline
logger = logging.getLogger(__name__)


def read():
    H, A = map(int, input().strip().split())
    return H, A


def solve(H, A):
    ans = 0
    n_slimes = 1
    while H > 0:
        H //= A
        ans += n_slimes
        n_slimes <<= 1
    return ans


if __name__ == "__main__":
    inputs = read()
    outputs = solve(*inputs)
    if outputs is not None:
        print("%s" % str(outputs))