First of all, well done on wanting to read English literature to improve your English level! You could give a go to "The Curious Incident of the Dog in the Night" by Mark Haddon since it's an easy read. The language used in the book is simple and easy to understand. Another option would be "The Old Man and the Sea" by Ernest Hemingway. It used to be my favorite book when I was a kid because it was about a battle between a fisherman and a giant fish. It's like a fable, and it's all about courage, survival, and triumph. Again, the language is perfect for beginners, and you'll find it very accessible to read! I would also recommend solving some englishlinx English worksheets because that's another very fun and intelligent way to learn a language. Good luck!