public class AtoB {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String[] items = br.readLine().split(" ");
String a = items[0];
String b = items[1];
int answer = 1;
while(Integer.parseInt(a) < Integer.parseInt(b)) {
if(b.charAt(b.length() - 1) == '1') {
b = b.substring(0, b.length() - 1);
answer++;
} else if(Integer.parseInt(b) % 2 == 0){
b = String.valueOf(Integer.parseInt(b) / 2);
answer++;
} else {
break;
}
}
if(a.equals(b)) {
System.out.println(answer);
} else {
System.out.println(-1);
}
}
}
a: 100
b: 200
ex) 40021 -> 4002 -> 2001 -> 200 -> 100