#include <iostream>

using namespace std;

int main() {
    int a, b;
    cin >> a >> b;

    int cnt = 0; 
    while (b >= a) {
        if (b % 10 == 1) {
            b /= 10;
        } else if (b % 2 == 0) {
            b /= 2;
        } else {
            break;
        }
        cnt++;
    }

    if (a == b) {
        cout << cnt+1 << endl;
    } else {
        cout << -1 << endl;
    }

    return 0;
}