Revision d2c5466f-c627-4c1b-aa49-80f6548a5b9c - Stack Overflow

I am beginner in Python programming and because of that i need some help.

I try to resolve a simple problem.
Enter two numbers from keyboard with at least three digits. 
Print the number that have the digits sum greater.

In the title i said that the "function is not executed".
I said that because inside of function i have tried to print the values of variables.
The values of those variables is not printed, so i think that the function is not executed.

Thank in advance. 

And my code is :

 a = input('\n Enter the first number : ' )
 x = sum([a])
 print('\n The sum of the digits number ' +str(x)+ ' este : %d' %x)

 b = input('\n Enter the second number : ')
 y = sum([b])
 print('\n The sum of the digits number ' +str(y)+ ' este : %d' %y)

 def sum(param):
 var = 0
 while(param != 0):
 var += (param % 10)
 print(var)
 param /= 10
 print(param)
 return var