The radius of the smallest circle which touches the parabolas \( y = x^{2} + 2 \) and \( x = y^{2} + 2 \) is:
\( \frac{7\sqrt{2}}{4} \)
\( \frac{7\sqrt{2}}{2} \)
\( \frac{7\sqrt{2}}{8} \)
\( \frac{7\sqrt{2}}{16} \)