There are N children in AtCoder Kindergarten. Mr. Evi will arrange the children in a line, then give 1 candy to the first child in the line, 2 candies to the second child, ..., N candies to the N-th child. How many candies will be necessary in total?
n = int(input())
for i in range(n+1) :
  i = i + n
  print(i)
n = int(input())
cnt = 0
 
for i in range(n + 1) :
  cnt += i
print(cnt)