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())
print(N*(N+1)/2)
N = int(input())
print(N*(N+1)//2)