x,y,h = map(int,input().split())
X = x
Y = y
H = h/1000
a = max(X,Y)
b = min(X,Y)
cnt2 = 0
while b > H:
    b /= 2
    H *= 2
    cnt2 += 1
while a > H:
    a /= 2
    H *= 2
    cnt2 += 1
print(cnt2)