# -*- coding: utf-8 -*-
n, k = [int(i) for i in input().split()]
gamed = 1
res = n - 1
t = 0
while res > 0:
    if gamed >= k and k <= res:
        gk = res // k
        res %= k
        gamed += gk*k
        t += gk
        continue
    g = min(gamed, k, res)
    gamed += g
    res -= g
    t += 1
print(t)