If the foot of the perpendicular drawn from \( (1, 9, 7) \) to the line passing through the point \( (3, 2, 1) \) and parallel to the planes \( x + 2y + z = 0 \) and \( 3y - z = 3 \) is \( (\alpha, \beta, \gamma) \), then \( \alpha + \beta + \gamma \) is equal to:
