title: Sum of two numbers from a .txt file (Python2)
body: <p>I have a question about writing a Python program to have the sum of 2 numbers from a txt file. (This question was from the Australian Informatics Olympiad Training Website)</p>
  
  <p>The Input File is: addin.txt
  and the Output File is: addout.txt</p>
  
  <p>Input:
  The input file will consist of the two integers a and b separated by a single space. It is guaranteed that 0 &lt;= a, b &lt;= 1,000,000,000. </p>
  
  <p>Output:
  The output file should consist of a single integer, the sum of a and b. </p>
  
  <p>Sample Input:
      23 45
  Sample Output:
      68</p>
  
  <p>So far, I know how to read and write from txt files but I don't know how it would read the two numbers in the input separately.</p>
  
  <p>Is it possible anyone could show me a program that would fit with this criteria? (Preferable with comments so I can understand it)</p>
  
  <p>Thanks in advance for anyone's help!</p>