import java.util.Scanner;
class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int num = sc.nextInt(),count = 0;
		
		if(num == 1) {
			System.out.println(0);
			return;
		}
		
		int c = 1;
		while(true) {
				if(num - c <= c) {
					System.out.println(count + 1);
					return;
				}
				if(num - c > c) {
					c *= 2;
					count++;
				}
		}
	}
}