#include <stdio.h>

int main() {
    int A, B;
    scanf("%d %d",&A, &B);

    int flag = 0;
    int count = 1;
    while(B >= A) {
        if (A==B) {
            flag = 1;
            break;
        }
        
        if (B%2==0) {
            B /= 2;
            count++;
        }
        else if (B%10==1) {
            B /= 10;
            count++;
        }
        else break;
    }

    printf("%d\n", flag ? count : -1);

    return 0;
}