(11) - Incoming and Outcoming. (Corrected once)

$\text{M}$ and $\text{N}$ are respectively points on the circumscribed circle and incircle of $\square{\text{ABCD}}$ . Calculate the value of

$\large \dfrac{\text{MA}^4 + \text{MB}^4 + \text{MC}^4 + \text{MD}^4}{2(\text{NA}^2\text{NC}^2 + \text{NB}^2\text{ND}^2)}$