def gcd(n, m):
    if m == 0:
        return n
    return gcd(m, n % m)

def main():
    N = int(input())
    M = int(input())
    g = gcd(N, M)
    N //= g
    M //= g
    M2 = 0
    M5 = 0

    if N % M == 0:
        N //= M
        while N % 10 == 0:
            N //= 10
            print(N)
    else:
        N %= M
        while M % 2 == 0:
            M //= 2
            M2 += 1
        while M % 5 == 0:
            M //= 5
            M5 += 1

        if M != 1:
            print(-1)
        else:
            while M2 < M5:
                M2 += 1
                N *= 2
                N %= 100000000
                while N % 10 == 0:
                    N //= 10

            while M2 > M5:
                M5 += 1
                N *= 5
                N %= 1000000000
                while N % 10 == 0:
                    N //= 10

            print(N)

if __name__ == '__main__':
    main()