找规律 SGU 126 Boxes

题目地址：http://acm.sgu.ru/problem.php?contest=0&problem=126

 /*
     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 ;
 }