Let \( S \) and \( S' \) be the foci of the ellipse \( \frac{x^2}{25} + \frac{y^2}{9} = 1 \) and \( P(\alpha, \beta) \) be a point on the ellipse in the first quadrant. If \( (SP)^2 + (S'P)^2 - SP \cdot S'P = 37 \), then \( \alpha^2 + \beta^2 \) is equal to:
