> # Challenge template
Given an input of [...INPUT...], [...OUTPUT/ACTION...].
Define any necessary terms. Also show any necessary diagrams, tables, formulas, etc. here.
Describe the process of transformating the input to the output or of performing the action on the input.
Give any constraints on the input / output. Make sure there is no ambiguity in what input / output is allowed (this can mean granting extra permissions / liberties on what constitues acceptable input / output).
Cover any extra rules or restrictions that haven't already been mentioned. This section is optional and, …