def ex_euclid(x, y):
    c0, c1 = x, y
    a0, a1 = 1, 0
    b0, b1 = 0, 1

    while c1 > 0:
        q, r = divmod(c0, c1)

        c0, c1 = c1, r
        a0, a1 = a1, (a0 - q * a1)
        b0, b1 = b1, (b0 - q * b1)

    return c0, a0, b0

def crt(x1, y1, x2, y2):
    gcd, a, b = ex_euclid(y1, y2)
    lcm = y1 * y2 // gcd
    
    c = x2 - x1
    if c % gcd != 0:
        return -1, lcm
    
    n = (y1 * c * a // gcd + x1) % lcm
    return n if n > 0 else lcm, lcm

def solve(x1, y1, x2, y2, x3, y3):
    x12, y12 = crt(x1, y1, x2, y2)
    if x12 < 0:
        return x12
    x123, y123 = crt(x12, y12, x3, y3)
    return x123

x1, y1 = map(int, input().split())
x2, y2 = map(int, input().split())
x3, y3 = map(int, input().split())

print(solve(x1, y1, x2, y2, x3, y3))