import java.util.Scanner;

public class Main{
	public static void main(String[] args) {
		//System.out.println("数字");
		Scanner scanner = new Scanner(System.in);
		int N = scanner.nextInt();
		scanner.close();
		int n = 0;
		int y;
		boolean flag = true;
		// while文の繰り返し回数を20未満とした
		while(flag) {
			y = N - (int) Math.pow(2, n);
			if(y <= 0) {
				break;
			}
			if(n > 20) {
				flag = false;
			}
			n++;
		}
		System.out.println(n);
	}
}