# DUE TUESDAY 24th 11:59PM******
# Alec Greenaway -- CS 161
# Input = allow user to type in an input n, that is a positive integer
# Output = 1-2+3-4+5-6+7-8+9-10.......+/- n

# Variables:
negNum = 0
posNum = 0
numList = []
counterList = []
counter = 1
n = float(input("Enter a positive integer"))
if (n < 0):
    exit("Positive vibes only")
lastNum = n
finalString = ''

# creates a list of all the integer leading up to the chosen integer

while (counter <= lastNum):
    numList.append(counter)
    counter = counter + 1

# Makes even numbers negative, and keeps odd ones postive, and then calculates the sums of each:
# Also build a string list that adds the correct operator to the end of number for printing purposes
for num in range(0, len(numList)):
    if (numList[num] % 2 == 0):
        negNum += numList[num] * (-1)
        finalString += str(numList[num]) + "+"
    else:
        posNum += numList[num]
        finalString += str(numList[num]) + "-"

# Takes off un-needed operator at the end
finalString = finalString[:-1]

# Prints a string of all the values up to n
# Prints grand total of pos/neg numbers up to n
print(finalString)
print("Final Sum:", negNum + posNum)