import sys
input=lambda: sys.stdin.readline().rstrip()
n=int(input())
m=int(input())
if n%m==0:
  nm=str(n//m)
  for nn in nm[::-1]:
    if nn=="0":
      continue
    else:
      print(nn)
      break
else:
  while True:
    if m%5==0:
      m//=5
      n*=2
    elif m%2==0:
      m//=2
      n*=5
    else:
      break
  if m==1:
    n=str(n)
    for nn in n[::-1]:
      if nn=="0":
        continue
      else:
        print(nn)
        break
  else:
    print(-1)