from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N = int(input())
M = int(input())
X = Counter([])
Y = Counter([])
while N%5==0:
    N//=5
    X[5] += 1
while N%2==0:
    N//=2
    X[2] += 1    


while M%5==0:
    M//=5
    Y[5] += 1
while M%2==0:
    M//=2
    Y[2] += 1   

if M!=1:
    if N==M:
        print(1)
    else:
        print(-1)
    exit()

m = min(X[2],X[5])
X[2] -= m
X[5] -= m

m = min(Y[2],Y[5])
Y[2] -= m
Y[5] -= m

m = min(X[2],Y[2])
X[2] -= m
Y[2] -= m
m = min(X[5],Y[5])
X[5] -= m
Y[5] -= m

K = max(Y.values())
X[5] += K - Y[5]
X[2] += K - Y[2]
N *= pow(5,X[5])*pow(2,X[2])
S = str(N)
for s in S[::-1]:
    if s!='0':
        print(s)
        exit()