#http://coderbyte.com/CodingArea/GuestEditor.php?ct=Simple%20Adding&lan=Python
'''
Using the Python language, have the function SimpleAdding(num) add up all the numbers from 1 to num. For the test cases, the parameter num will be any number from 1 to 1000. 
Use the Parameter Testing feature in the box below to test your code with different arguments.
Input = 12 Output = 78
Input = 140 Output = 9870
''' 
n = raw_input('Input number:'); print int(n)*(int(n)+1)/2

