Help me in solving LB01A problem

help
,
1

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.
A,C=map(int,input().split())
B=(A+C)/2
if :
    print(B)
else:
    print("-1")

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

2

Please click next to proceed.