import java.util.Scanner;

public class Yuki047 {
    public static void main(String[] args) {
        Yuki047 hoge = new Yuki047();
    }

    Yuki047() {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int count = 0;
        int k = 1;
        while (k < N) {
            count++;
            k *= 2;
        }
        System.out.println(count);
    }

}