#!/usr/bin/env python3

import collections
import math


Equation = collections.namedtuple("Equation", "x y")
NOSOL = -1


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


def solve(eq1, eq2, eq3):
    for i in range(eq2.y + 1):
        cand12 = eq1.x + eq1.y * i
        if cand12 > 0 and cand12 % eq2.y == eq2.x:
            sol12 = cand12
            lcm12 = lcm(eq1.y, eq2.y)
            break
    else:
        return NOSOL
    for j in range(eq3.y + 2):
        cand123 = sol12 + lcm12 * j
        if cand123 > 0 and cand123 % eq3.y == eq3.x:
            return cand123
    else:
        return NOSOL


def main():
    eq1 = Equation(*map(int, input().split()))
    eq2 = Equation(*map(int, input().split()))
    eq3 = Equation(*map(int, input().split()))
    print(solve(eq1, eq2, eq3))


if __name__ == '__main__':
    main()