x,y,h = map(int,input().split())
if x > y:#xの方を小さく
    tmp = x
    x = y
    y = tmp

cnt = 0

while x > h/1000:
    cnt += 1
    h *= 2
    x /= 2

while y > h/1000:
    cnt += 1
    h *= 2
    y /= 2

print(cnt)