Help me in solving PYTHCL134 problem

My issue

def multiply(a, b):
return(ab)

def sum(a, b):
return(a+b)

def abs_diff(a,b):
if a > b:
return (a - b)
else
return (b-a)

A, B = map(int, input().split())
C = multiply(A, B)
D = sum(A, B)
E = abs_diff(C, D)
print(E)

My code

# Debug the code below to solve the problem

Learning course: ATT - Python
Problem Link: Coding problem-4 in ATT - Python