Character input
Depending on what the task specifies, character input can be given in two ways:
as text or as an array. When text is requested, all characters
belonging to the keyword, including blanks and comma's, are treated as a single
element.
In the case of an array, the elements must be separated by blanks or comma's.
If the input should contain special characters like (leading) blanks or
equals signs, it can be quoted using back-quotes (`).
Normally character input is case-sensitive,
i.e. uppercase and lowercase letters have different meanings,
but individual tasks can deviate
from this or convert to either uppercase or lowercase.
