#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, srt, end) for (long long i = (srt); i < (long long)(end); i++)

int main(){
    double x, y, z;
    cin >> x >> y >> z;
    z /= 1000;
    ll ans = 0;
    while(x > z){
        x /= 2;
        z *= 2;
        ans++;
    }
    while(y > z){
        y /= 2;
        z *= 2;
        ans++;
    }
    cout << ans << endl;
    return 0;
}