import java.util.Scanner;
 
class Main {
	int n;
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		Main m = new Main(n);
		System.out.println(m.pocket(1));
	}
	Main(int n){
		this.n = n;
	}
	int pocket(int num){
		if(num*2<n){
			return 1 + pocket(num*2);
		} else {
			return num==1?0:1;
		}
	}
}