cf B. Fox Dividing Cheese

http://codeforces.com/contest/371/problem/B
 1 #include <cstdio>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <algorithm>
 5 #define ll int
 6 using namespace std;
 7 
 8 ll a,b;
 9 int ans=0;
10 int m1,m2;
11 int check(ll x)
12 {
13     while(x)
14     {
15         if(x%2==0)
16         x/=2;
17         else if(x%3==0)
18         x/=3;
19         else if(x%5==0)
20         x/=5;
21         else
22         {
23            break;
24         }
25         ans++;
26     }
27     return x;
28 }
29 
30 ll gcd(ll c,ll d)
31 {
32     return d==0?c:gcd(d,c%d);
33 }
34 
35 int main()
36 {
37     cin>>a>>b;
38     if(a==b)
39     {
40         printf("0
");
41         return 0;
42     }
43     int s=gcd(a,b);
44     a/=s;
45     b/=s;
46     if(check(a)==check(b))
47     {
48         printf("%d
",ans);
49     }
50     else printf("-1
");
51     return 0;
52 }
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