For my anniversary,
I decided to surprise my husband since he is a voracious reader,
I decided to collect a lot of books for him.
On the first day of the month, I bought one book,
on the second, I bought two and
on the third, I bought three.
This process went on till the anniversary and on the day,
I had 276 books with me to gift him.
Can you calculate, on which day is our anniversary?
Anniversary is on 23rd day of the month.