import java.util.Scanner;

public class No47 {
	
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		 
		int N= sc.nextInt();
		
		int count=0;
		int k = 1;
		while(k<N){
			count++;
			k=k*2;
		}
			
			System.out.println(count);
		
	}

}