#region Header
#!/usr/bin/env python3
# from typing import *

import sys
import io
import math
import collections
import decimal
import itertools
import bisect
import heapq


def input():
    return sys.stdin.readline()[:-1]


# sys.setrecursionlimit(1000000)
#endregion

# _INPUT = """# paste here...
# """
# sys.stdin = io.StringIO(_INPUT)

def inv_gcd(a, b):
    a %= b
    if a == 0: return b, 0
    # 初期状態
    s, t = b, a
    m0, m1 = 0, 1
    while t:
        # 遷移の準備
        u = s // t

        # 遷移
        s -= t * u
        m0 -= m1 * u

        # swap
        s, t = t, s
        m0, m1 = m1, m0

    if m0 < 0: m0 += b // s
    return s, m0


# def crt(r: typing.List[int], m: typing.List[int]) -> typing.Tuple[int, int]:
def crt(r, m):
    assert len(r) == len(m)

    n = len(r)

    # Contracts: 0 <= r0 < m0
    r0 = 0
    m0 = 1
    for i in range(n):
        assert 1 <= m[i]
        r1 = r[i] % m[i]
        m1 = m[i]
        if m0 < m1:
            r0, r1 = r1, r0
            m0, m1 = m1, m0
        if m0 % m1 == 0:
            if r0 % m1 != r1:
                return (0, 0)
            continue

        # assume: m0 > m1, lcm(m0, m1) >= 2 * max(m0, m1)

        '''
        (r0, m0), (r1, m1) -> (r2, m2 = lcm(m0, m1));
        r2 % m0 = r0
        r2 % m1 = r1
        -> (r0 + x*m0) % m1 = r1
        -> x*u0*g % (u1*g) = (r1 - r0) (u0*g = m0, u1*g = m1)
        -> x = (r1 - r0) / g * inv(u0) (mod u1)
        '''

        # im = inv(u0) (mod u1) (0 <= im < u1)
        g, im = inv_gcd(m0, m1)

        u1 = m1 // g
        # |r1 - r0| < (m0 + m1) <= lcm(m0, m1)
        if (r1 - r0) % g:
            return (0, 0)

        # u1 * u1 <= m1 * m1 / g / g <= m0 * m1 / g = lcm(m0, m1)
        x = (r1 - r0) // g % u1 * im % u1

        '''
        |r0| + |m0 * x|
        < m0 + m0 * (u1 - 1)
        = m0 + m0 * m1 / g - m0
        = lcm(m0, m1)
        '''

        r0 += x * m0
        m0 *= u1  # -> lcm(m0, m1)
        if r0 < 0:
            r0 += m0

    return (r0, m0)

def main():
    X1, Y1 = map(int, input().split())
    X2, Y2 = map(int, input().split())
    X3, Y3 = map(int, input().split())
    r, m = crt([X1, X2, X3], [Y1, Y2, Y3])
    if r == 0 and m == 0:
        print(-1)
    else:
        print(r)

if __name__ == '__main__':
    main()