How to get rid of ants through bedroom window?

We are in summer. It's about 24°C.

I came home to my windowsill covered in ants. They're coming through the left corner hole at the bottom of the window where you open it.

I probably had this 5 years ago.

My family think pest control is a wast of money.

I've been using an ant cream but 1000s more have come and it's crawling along the wall going down to the skirting.

Should I use fly spray cause it looks awful and don't want to sleep in my room.

How to get rid of ants through bedroom window?
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