Two little greedy bears have found two pieces of cheese in the forest of weight *a* and *b* grams, correspondingly. The bears are so greedy that they are ready to fight for the larger piece. That's where the fox comes in and starts the dialog: "Little bears, wait a little, I want to make your pieces equal" "Come off it fox, how are you going to do that?", the curious bears asked. "It's easy", said the fox. "If the mass of a certain piece is divisible by two, then I can eat exactly a half of the piece. If the mass of a certain piece is divisible by three, then I can eat exactly two-thirds, and if the mass is divisible by five, then I can eat four-fifths. I'll eat a little here and there and make the pieces equal". 

The little bears realize that the fox's proposal contains a catch. But at the same time they realize that they can not make the two pieces equal themselves. So they agreed to her proposal, but on one condition: the fox should make the pieces equal as quickly as possible. Find the minimum number of operations the fox needs to make pieces equal.
The first line contains two space-separated integers *a* and *b* (1 ≤ *a*, *b* ≤ 10<sup class="upper-index">9</sup>).
from math import *
b = input()
b = b.split()
n = int(b[0])
m = int(b[1])
b = [2,3,5]
a = []
c = []
for x in range(10):
    a.append(0)
    c.append(0)
for x in b:
    l = n
    while (l%x)==0:
        a[x]+=1
        l/=x
    l = m
    while (l%x)==0:
        c[x]+=1
        l/=x
ans = 0
for x in b:
    if a[x]!=c[x]:
        l = abs(a[x]-c[x])
        ans+=l
        if a[x]<c[x]:
            for y in range(l):
                m/=x
        else:
            for y in range(l):
                n/=x
if n==m: print(ans)
else: print(-1)