/*

     找规律，智商不够，看了题解

     详细解释：http://blog.csdn.net/ahfywff/article/details/7432524

 */

 #include <cstdio>

 #include <cmath>

 #include <cstring>

 #include <string>

 #include <iostream>

 #include <algorithm>

 #include <queue>

 #include <vector>

 using namespace std;

 const int MAXN = 1e5 + ;

 const int INF = 0x3f3f3f3f;

 int GCD(int a, int b)

 {

     return b ? GCD (b, a % b) : a;

 }

 int main(void)        //SGU 126 Boxes

 {

     //freopen ("C.in", "r", stdin);

     int n, m;

     while (~scanf ("%d%d", &n, &m))

     {

         int ans;

         if (n ==  || m == )

         {

             ans = ;

         }

         else

         {

             if (n < m)  swap (n, m);

             int k = GCD (n, m);

             int x = n / k;  int y = m / k;

             if ((x+y) & )

             {

                 ans = -;

             }

             else

             {

                 int tmp = x + y;

                 ans = ;

                 while (tmp > )

                 {

                     if (tmp %  == )

                     {

                         tmp /= ;

                         ans++;

                     }

                     else

                     {

                         ans = -;    break;

                     }

                 }

             }

         }

         printf ("%d\n", ans);

     }

     return ;

 }