from math import log

x, y, h = map(int, input().split())
if x > y:
    x, y = y, x

x, y = map(lambda x: x*1000, [x, y])
times = 0

times += int(log(x / h) / log(4))
if log(x / h) / log(4) - times > 0:
    times += 1

tmp = times
times += int(log(y / (h * (2 ** tmp))) / log(4))
if (log(y / (h * (2 ** tmp))) / log(4)) - times + tmp > 0:
    times += 1

print(times)