In the language R: what is the code for this? `x` is greater than 3 and `y` is less than or equal to 3 then print "Hello world!"

* Otherwise if `x` is greater than 3 print "!dlrow olleH"

* If `x` is less than or equal to 3 then print "Something else ..."

* Stop execution if x is odd and y is even and report an error, don't print any of the text strings above.