#include<iostream>

using namespace std;

int main(void){
  int n;
  int bis;
  int count;

  bis=1;
  count=0;
  cin>>n;

  while(1){
    if(bis<n){
      bis=bis*2;
      count++;
    }else{
      break;
    }
  }

  cout<<count<<endl;

  return 0;
}