import java.util.Scanner;

public class Question47 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		double fN = (double)N;

		int count = 0;
		while (fN > 1){
			fN /= 2;
			count++;
		};

		System.out.println(count);
	}

}