Change the number of PAGES on the front page

Hello
I’m usine the theme Asteria on this website : https://www.pancartes-de-la-honte-pour-chats.com/

you will see after the front posts, at the end, before the adsence add and the footer, the number of pages with all my others posts (19 actually). I would like to limit this number, for example have only the 15 latest pages : I tried to find where I could change something but no result… That’s why I’m writting here to have some answer
Thank you ??
Claire