import java.util.Scanner;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int result = 0;
		int bit = 1;
		while (n > bit) {
		    bit <<= 1;
		    result++;
		}
		System.out.println(result);
	}
}