Nim game

You are encouraged to solve this task according to the task description, using any language you may know.
Nim is a simple game where the second player ─── if they know the trick ─── will always win.



The game has only 3 rules:

   start with   12   tokens
   each player takes   1,  2,  or  3   tokens in turn
  the player who takes the last token wins.


To win every time,   the second player simply takes 4 minus the number the first player took.   So if the first player takes 1,   the second takes 3 ─── if the first player takes 2,   the second should take 2 ─── and if the first player takes 3,   the second player will take 1.



Task

Design a simple Nim game where the human player goes first, and the computer always wins. The game should enforce the rules.




import os { input }
 
fn show_tokens(tokens int) {
    println('Tokens remaining $tokens\n')
}
 
fn main() {
    mut tokens := 12
    for {
        show_tokens(tokens)
        t := input('  How many tokens 1, 2, or 3? ').int()
        if t !in [1, 2, 3] {
            println('\nMust be a number between 1 and 3, try again.\n')
        } else {
            ct := 4 - t
            mut s := 's'
            if ct == 1 {
                s = ''
            }
            println('  Computer takes $ct token$s \n')
            tokens -= 4
        }
        if tokens == 0 {
            show_tokens(0)
            println('  Computer wins!')
            return
        }
    }
}