Problem 690. Remove the two elements next to NaN value

The aim is to remove the two elements next to NaN values inside a vector.

For example:

 x = [6 10 5 8 9 NaN 23 9 7 3 21 43 NaN 4 6 7 8]

The output y will be:

 y = [6 10 5 8 9 7 3 21 43 7 8]

Nan values and the 2 next elements after the NaN (23-9 and 4-6) have been removed.

There will be always NaN values in the input vector followed by at least 2 integers.