Card game

You will be building a program to play a card game.
The objective of the game is to form a hand of three
cards that for each of three different properties are
either all the same or all different.

The properties of a card are:

1. Prefix: "+", "-", or "="
2. Letter: "A", "B", or "C"
3. Number of letters: 1, 2, or 3 (e.g. A, AA, AAA)

For example, given the following set of cards

> -A -B -BB +C -C -CC =CCC

there are two possible hands:

1. `+C -CC =CCC`
  * prefix: +,-,= are all different
  * letter: C, C, C are all the same
  * number of letters: 1, 2, 3 are all different

2. `-A -B -C`
  * Prefix: -, -, - are all the same
  * Letter: A, B, C are all different
  * Number of letters: 1, 1, 1 are all the same

Specifications:
- You only need to find one hand
- The cards should be read from STDIN, each card is separated by a space
- Print the hand you find to STDOUT, space separated (trailing space is ok)
- Cards may appear in any order in the input
- Cards may be output in any order