#!/usr/bin/env python3
import math
lcm = lambda a, b: a * b // math.gcd(a, b)
def extgcd(a, b):
    if b == 0:
        return 1, 0
    else:
        na, nb = extgcd(b, a % b)
        return nb, na - a//b * nb
def modinv(a, n):
    return extgcd(a, n)[0] % n
def crt(eqn1, eqn2):
    x1, m1 = eqn1
    x2, m2 = eqn2
    d = math.gcd(m1, m2)
    x = x1 + (m1 // d) * (x2 - x1) * modinv(m1 // d, m2 // d)
    m = lcm(m1, m2)
    return x % m, m
eqn = [ tuple(map(int, input().split())) for _ in range(3) ]
ans, _ = crt(eqn[0], crt(eqn[1], eqn[2]))
if ans == 0:
    ans += lcm(eqn[0][1], lcm(eqn[1][1], eqn[2][1]))
for x, y in eqn:
    if ans % y != x:
        ans = -1
        break
print(ans)