def ChineseRem(b1, b2, m1, m2):
    from math import gcd

    def extGCD(a, b):
        # ax + by = gcd(a, b)の解を求める
        if b == 0:
            return 1, 0
        q = a // b
        r = a % b
        X, Y = extGCD(b, r)
        return Y, X - q * Y

    if (b1 - b2) % gcd(m1, m2) != 0:
        return None, None
    d = gcd(m1, m2)
    lcm = m1 * m2 // d
    p, q = extGCD(m1, m2)
    return ((b2 - b1) // d * m1 * p + b1) % lcm, lcm


X, M = [0] * 3, [0] * 3
for i in range(3):
    X[i], M[i] = map(int, input().split())

x, mod = ChineseRem(X[0], X[1], M[0], M[1])
if x is None:
    print(-1)
else:
    ans, lcm = ChineseRem(x, X[2], mod, M[2])
    if ans is None:
        print(-1)
    else:
        if ans == 0:
            print(lcm)
        else:
            print(ans)