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?

-----Constraints-----
 - 1≦N≦100

-----Input-----
The input is given from Standard Input in the following format:
N

-----Output-----
Print the necessary number of candies in total.

-----Sample Input-----
3

-----Sample Output-----
6

The answer is 1+2+3=6.

Difficulty: EASY

Solutions:
from sys import stdin
input = stdin.readline
N = int(input())
if N % 2 == 1:
	print(N * (N + 1) // 2)
else:
	print((N + 1) * N // 2)


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


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


n = int(input())
print(-~n * n // 2)


n = int(input())
print(int(n * (n + 1) * 0.5))


a = input()
b = int(a)
c = (b + 1) * b // 2
print(c)


from sys import stdin, stdout
from time import perf_counter
import sys
sys.setrecursionlimit(10 ** 9)
mod = 10 ** 9 + 7
n = int(input())
resutl = n * (n + 1) // 2
print(resutl)


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


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


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


val1 = int(input())
print(int(val1 * (val1 + 1) / 2))


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


n = int(input())
print(n * -~n >> 1)


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


import math
n = int(input())
print(math.floor(n / 2 * (n + 1)))


f = lambda x: x * (x + 1) // 2
print(f(int(input())))


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


import math
N = int(input())
sum = math.floor(N * (1 + N) / 2)
print(sum)


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


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


a = int(input())
print(int(0.5 * a * (a + 1)))


print((int(input()) * 2 + 1) ** 2 // 8)


import math
from datetime import date

def main():
	n = int(input())
	print(n * (n + 1) // 2)
main()


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


import sys
import math
sys.setrecursionlimit(10 ** 8)
ini = lambda : int(sys.stdin.readline())
inm = lambda : map(int, sys.stdin.readline().split())
inl = lambda : list(inm())
ins = lambda : sys.stdin.readline().rstrip()
debug = lambda *a, **kw: print('\x1b[33m', *a, '\x1b[0m', **dict(file=sys.stderr, **kw))
N = ini()
print(int(N * (N + 1) / 2))


n = int(input())
print('{:.0f}'.format(n * (n + 1) / 2))


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


x = int(input())
print(int((x ** 2 + x) / 2))


def main():
	n = int(input())
	ans = int(n * (n + 1) / 2)
	print(ans)

def __starting_point():
	main()
__starting_point()