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)