#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define INF 1000000000
#define mod 1000000007
using ll=long long;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    //これ賢い賢すぎる．怖い
    unsigned long long x,y,h,ans=0;cin>>x>>y>>h;x*=1000;y*=1000;
    if(x>y) swap(x,y);

    // x=x/2, y=y,h=h*2
    // x=x, y=2*y, h=h*4とすればよい
    while(x>h){
        ans++;y*=2;h*=4;
    }
    while(y>h){
        ans++;x*=2;h*=4;
    }
    cout<<ans<<endl;
    return 0;
}