How to use conditional check / number comparison with guard

[ericsen oei]

Excuse me,

I am currently doing  Lab 5
I am trying to check if the number input by users is 1, then answer accordingly.

Here's the code that I attempted:

@: animal
animal: duck|ducks rabbit|rabbits chicken|chickens horse|pony|horses|ponies alligator|alligators

assoc: feet

{{
   :duck 2
   :rabbit 4
   :chicken 2
   :horse 4
   :ducks 2
}} +feet

Q: $x.@int $animal
A: ${ $x int 1 > } ? % $animal have ${ $x int $animal feet * } feet
A: $animal has ${ $animal feet } feet
--
Q: $animal
A: $animal has ${ $animal feet } feet
--

However when I test in the main.m with 2 ducks as input.
It gives me two errors

ERROR: Attempting to use the compilation word 'THEN' in interpretation mode.

ERROR: null

How could I make this works??

Thanks in advance for the help