x, y, h = map(int, input().split())
h = h /1000
count = 0
while True:
    if x < h:
        break
    else:
        x /= 2
        h *= 2
        count += 1

while True:
    if y < h:
        break
    else:
        y /= 2
        h *= 2
        count += 1

print(count)