STATUS OF BOX

There are $ N $ boxes kept in a room which are labelled $1$ to $N$. There are also $ N$ people who are numbered $ 1 $ to $ N$ standing in a line outside the room according to their numbers. Person $1$ enters the room and opens all the boxes. Then person 2 enters and closes box numbers $ 2,4,6,....$ Then person 3 enters and changes status of box numbers $3,6,9,......$ (Changing status