#include <iostream>
#include <cstdio>
using namespace std;

long long x,y,k,br;

int main()
{
    freopen("symbiosis.in","rt",stdin);
     freopen("symbiosis.out","wt",stdout);
    cin>>x>>y>>k;
    while(y > 0){
        y=y-(x*k);
        x+=x/2;
        br++;
    }
    br--;
    cout<<br<<endl;

    return 0;
}