def gcd(a, b):
    if b == 0:
        return a
    else:
        return gcd(b, a%b)

def extgcd(a, b):
    #拡張ユークリッド互除法
    #ax + by = gcd(a, b)となる(x, y)を求めます
    if b == 0:
        return [1, 0]

    q = a//b
    r = a%b
    
    s, t = extgcd(b, r)
    y = s - q*t
    return [t, y]

def CRT(b, m):
    r = 0
    M = 1
    for i in range(len(b)):
        d = gcd(M, m[i])
        p, q = extgcd(M, m[i])

        if (b[i] - r)%d != 0:
            print(-1)
            exit(0)

        t = (b[i] - r)//d * p % (m[i]//d)
        r += M * t
        M *= m[i]//d
    
    return r%M

x = []
y = []
for i in range(3):
    X, Y = map(int, input().split())
    x.append(X)
    y.append(Y)

print(CRT(x, y))