#include <iostream>
using namespace std;
//http://www.musashinodenpa.com/arduino/ref/index.php?f=0&pos=785

int main(){
   int n;
   cin >> n;
   for(int i = 0;i < 30;i++){
      if((n - 1) >> i == 0){
         cout << i << endl;
         return 0;
      }
   }
}