[백준] 16953번 A → B

import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		
		Scanner kb = new Scanner(System.in);
		
		String a = kb.next();
		String b = kb.next();
		int count = 1;
		
		while(!a.equals(b)) {
			
			if(Integer.parseInt(a)>Integer.parseInt(b)) {
				break;
			}
			
			char last = b.charAt(b.length()-1);
			if(last == '1') {
				b = b.substring(0, b.length()-1);
				count++;
			}else if(Integer.parseInt(b)%2 ==0) {
				int pro = Integer.parseInt(b)/2;
				b = String.valueOf(pro);
				count++;
			}else {
				break;
			}
		}
		
		if(!a.equals(b)) {
			System.out.println("-1");
		}else {
			System.out.println(count);
		}
	}


}