My website’s permalink structure is /%postname%/ and i want to create pemalink with number, for example for every new post i will create 1, 2, 3, etc permalink for newer posts. But right now when i create permalink with 1, 2 or 3 then system automatically add -2 after number, and it becomes 1-2, 2-2, 3-2.

WordPress is installed in subdirectory on nginx server and working fine.

What should i need to change?