If the equation of the circle having the common chord to the circles
$$
x^2 + y^2 + x - 3y - 10 = 0
$$
and
$$
x^2 + y^2 + 2x - y - 20 = 0
$$
as its diameter is
$$
x^2 + y^2 + \alpha x + \beta y + \gamma = 0,
$$
then find $ \alpha + 2\beta + \gamma $.