N = int(eval(input()))

num = 0

for i in range(1,N+1):

  num += i

print(num)
N = int(eval(input()))

print((sum([i for i in range(1, N+1)])))
N = int(eval(input()))
num = 0
for i in range(1, N + 1):
    num += i
print(num)

N = int(eval(input()))
print((sum([i for i in range(1, N + 1)])))

-num = 0 -for i in range(1, N + 1): -    num += i -print(num) +print((sum([i for i in range(1, N + 1)])))