Help me in solving LB02A problem

My issue

My code

# Step 1: Read and understand the problem statement and sample test cases

# Click on 'Next' once you are ready to proceed.
chicken = x legs
duck = y legs
chef farm = one type of bird
total birds = z legs
only chick = print chicken
only  duck = print duck
either chick or duck = print any
neither chick nor duck = print none

Learning course: Python for problem solving - 1
Problem Link: CodeChef: Practical coding for everyone