import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
       int n = koko.nextInt();
       int bis = 1;
       int count = 0;
       for(int i=0; i<30; i++){
           if(n>bis){
           bis = bis*2;
           count = count + 1;
       }else{
           break;
       }
       }
       System.out.println(count);
       }
       
    }