#include <iostream>
#include <math.h>
#define cmp(a, b) (a += b, b = a - b, a -= b)
#define mini 1e-8
using namespace std;

int main(){
    double x, y, h;
    cin >> x >> y >> h;
    if (x > y) cmp(x, y);
    x *= 1000, y *= 1000;
    
    int times = 0, i;
    times += log(x / h) / log(4);
    if ((log(x / h) + mini) / log(4) - (double)times != 0.0) times += 1;
    int tmp = times;
    times += log(y / (h * pow(2.0, tmp))) / log(4);
    if ((log(y / (h * pow(2.0, tmp))) + mini) / log(4) - (double)times != 0.0) times += 1;

    cout << times << endl;
    return 0;
}