import sys
from math import gcd
readline = sys.stdin.readline

def lcm(a, b):
    return a * b // gcd(a, b)

def extgcd(a, b):
    assert(a >= b)
    if b == 0:
        return 1, 0
    x, y = extgcd(b, a % b)
    return y, x - (a // b) * y

def crt(r, m):
    r0, m0 = 0, 1
    for r1, m1 in zip(r, m):
        if m0 < m1:
            r0, r1 = r1, r0
            m0, m1 = m1, m0
        d = gcd(m0, m1)
        if (r1 - r0) % d != 0:
            return 0, 0
        l = lcm(m0, m1)
        x0, _ = extgcd(m0, m1)
        r0 = r0 + m0 * x0 * (r1 - r0) // d
        r0 %= l
        m0 = l
    return r0, m0

def main():
    r, m = [0] * 3, [0] * 3
    for i in range(3):
        r[i], m[i] = map(int, readline().split())
    ans, lcm = crt(r, m)
    if lcm == 0:
        print(-1)
        return
    if ans == 0:
        ans += lcm
    print(ans)

if __name__ == "__main__":
    main()