local x, y, h = io.read("*n", "*n", "*n")
x = x * 1000
y = y * 1000
if y < x then x, y = y, x end
local xc, yc = 0, 0
do
  local xt, yt = h, h
  while xt < x do
    xt = xt * 2
    xc = xc + 1
  end
  while yt < y do
    yt = yt * 2
    yc = yc + 1
  end
end
local cnt = math.ceil(xc / 2)
yc = yc - cnt
cnt = cnt + math.ceil(yc / 2)
print(cnt)