import java.util.*;

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