#include<bits/stdc++.h>
#define _LIBCPP_DEBUG 0
using namespace std;
typedef long long int ll;
ll MOD = 1e9 + 7;
int INF = 1 << 20;


int main(void){

    double x,y,h; cin>>x>>y>>h;
    h /= 1000;
    ll cnt=0;
    while(x>h ||y>h){
        if(x>h){
            x/=2;
        }else{
            y/=2;
        }
        h*=2;
        cnt++;
    }
    cout<<cnt<<endl;
    
    return 0;
}