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

print((n*(n+1)//2))
print((sum([i for i in range(1, int(eval(input())) + 1)])))

n = int(eval(input()))
print((n * (n + 1) // 2))

-print((sum([i for i in range(1, int(eval(input())) + 1)]))) +n = int(eval(input())) +print((n * (n + 1) // 2))