#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;


int main(){
  double x, y, h;
  cin >> x >> y >> h;
  h /= 1000.0;
  if(x > y) swap(x,y);

  ll ret = 0;
  while(true){
    if(x > h){
      x /= 2;
      h *= 2;
      ret++;
    }
    else if(y > h){
      y /= 2;
      h *= 2;
      ret++;
    }
    else{
      break;
    }
  }

  cout << ret << endl;
  
  return 0;
}