/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	String N = Integer.toBinaryString(n);
    	System.out.println(((n & (n-1)) == 0) ? N.length() - 1 : N.length());
	}
}