#include<bits/stdc++.h>

using namespace std;
using ll = long long int;
using lc = complex<double>;

int main(void) {
    constexpr ll MOD = 1e9 + 7;
    constexpr double PI = acos(-1);
    cout << fixed << setprecision(32);
    cin.tie(0); ios::sync_with_stdio(false);

    ll x, y, h;
    cin >> x >> y >> h;
    ll r = 0;

    {
        if(x < y)
            while(1000*x > h)
                r++, h *= 4, y *= 2;
        if(x > y)
            while(1000*y > h)
                r++, h *= 4, x *= 2;

        while(1000*x > h)
            r++, h *= 4, y *= 2;
        while(1000*y > h)
            r++, h *= 4, x *= 2;
    }

    cout << r << endl;
}