input/output examples:
"hello" -> "h"
"world" -> "w"
arguments: x
solution: Left(input(x), 1)

input/output examples:
"hello" -> "o"
"world" -> "d"
arguments: x
solution: Right(input(x), 1)

input/output examples:
"hello", "you" -> "helloyou"
"world", "domination" -> "worlddomination"
arguments: x, y
solution: Concatenate(input(x), input(y))

input/output examples:
"hello", "you" -> "hello you"
"world", "domination" -> "world domination"
arguments: x, y
solution: Concatenate(Concatenate(input(x), " "), input(y))

input/output examples:
"hello" -> "ho"
"world" -> "wd"
"domination" -> "dn"
arguments: x
solution: Concatenate(Left(input(x), 1), Right(input(x), 1))