import sequtils, strutils, algorithm, math, future, sets, tables, hashes, intsets
let read = iterator : string {.closure.} = (while true: (for s in stdin.readLine.split : yield s))


var
    x,y,h = read().parsefloat
    maxv = int.low

h = h / 1000


proc isok(mid: int): bool = 
    for k in 0 .. mid:
        var
            a = x / (2.0 ^ k)
            b = y / (2.0 ^ (mid - k))
            vh = h * (2.0 ^ mid)
        if a * 2.0 > vh / 2.0 and b * 2.0 > h * 2.0 ^ (mid - k) / 2.0:
            return true
        if b * 2.0 > vh / 2.0 and a * 2.0 > h * 2.0 ^ (k) / 2.0 :
            return true

var
    ng = 41
    ok = 0
while abs(ok - ng) > 1:
    var
        mid = (ok + ng) div 2
    if isok(mid):
        ok = mid
    else:
        ng  = mid
    
echo ok