# coding: utf-8
# Your code here!
x,y,h=map(int,input().split())

x,y=min(x,y),max(x,y)

ans=0
while x*1000>h:
    x/=2
    h*=2
    ans+=1

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

print(ans)
#print(x,y,h)