def slope(self, other):
        """
        Determines the slope between this point and another point.

        Args:
            other (AffinePoint): The second point.

        Returns:
            int: Slope between self and other.
        """
        X1, Y1, X2, Y2 = self.X, self.Y, other.X, other.Y
        Y3 = Y1 - Y2
        X3 = X1 - X2
        return (Y3 * self.inverse(X3)) % self.P