I'm taking a python course and there is a question that requires adding a user's input.

The question is:

> 
> Sometimes a programmer does not know how many times data is to be
> entered. For example, suppose you want to create a program that adds
> an unspecified amount of positive numbers entered by the user. The
> program stops adding numbers when the user enters a zero or a negative
> number. Then the program prints the total. Before creating this
> program, review the three actions required for all loops:
> 
> 
> a. Initialize a variable that will be used in the test condition: What
> will be tested to determine if the loop is executed or not? Write a
> line of code that initializes a variable to be used in the test
> condition of the loop for this program. The variable should contain a
> value entered by the user.
> 
> 
> b. Include a test condition that causes the loop to end when the
> condition is false: What is the test condition for the while loop used
> in this program?
> 
> 
> c. Within the loop body, update the variable used in the test
> condition: Write the code for the loop body. Include the code to
> update the variable in the test condition.
> 
> 
> d. Complete the program. Enter and execute the code. Does it work
> properly?
> 
> 
> 

The code I have is:

```
while True:
  a = int(input("Enter a positive number: "))
  total = a + a
  if a>0:
    a+a

  else:
    print("The number you entered is a negative number or 0 \n The sum is: ", total)
    break

```

The program doesn't add all the values the user entered, how do I fix this?