Everywhere perfect square

A number $N$ is called good if it has the following properties

(1) It is consists of even number of digits (say $2n$ ).

(2) The number consists of first $n$ digits is a perfect square.The number consists of last $n$ digits is also a perfect square.

(3) The number itself a perfect square.

Find the sum of all such good numbers where $N < 10^4$