def extgcd(a, b):
    if b == 0:
        return (1, 0, a)
    X, Y, g = extgcd(b, a % b)
    return (Y, X - (a // b) * Y, g)

def chineserem(B, M):
    r = 0
    ALLM = 1
    for i in range(len(B)):
        x, y, g = extgcd(ALLM, M[i])
        if (B[i] - r) % g != 0:
            return (-1, -1)
        r += ((((B[i] - r) // g) * x) % (M[i] // g)) * ALLM
        ALLM *= (M[i] // g)
    return (r % ALLM, ALLM)

B = []
M = []
for i in range(3):
    x, y = map(int, input().split())
    B.append(x)
    M.append(y)
if max(B) == 0:
    print(chineserem(B, M)[1])
else:
    print(chineserem(B, M)[0])