Rishab and Pairs

Rishabh is obsessed with pairing things, he has an array $A$ of $2$*$N$ elements and he wants to pair them all into $N$ pairs such that for each pair, the sum of elements is even. Being an artist he is busy, so he would like you to tell him whether he can pair these elements or not. Formally, for a pair ($Ai$ and $Aj$) $Ai+Aj$ must be even and each element must be present in exactly one pair. ##