Problem Statement

Nim is a simple game where the second player─if they know the trick─will always win.

The game has only 3 rules:

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

Let's start with the solution: