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: introductory

Starter code:

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

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


ans=0
n=int(input())
for i in range(1,n+1):
	ans+=i
	
print(ans)


import math
from datetime import date

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


n=int(input())
a=0
for i in range(n+1):
  a+=i
print(a)

a = 0

x = int(input())
y = x+1
for i in range(y):
    a = a+i
 

print(a)

import sys
import math

#https://atcoder.jp/contests/agc008/submissions/15248942
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("\033[33m", *a, "\033[0m", **dict(file=sys.stderr, **kw))

N = ini()
print(int((N*(N+1))/2))
'''
sum = 0
for i in range(N):
    sum += (i+1)
print(sum)
'''

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

#!/usr/bin/env python3
import sys


def solve(N: int):
    return sum(range(1, N+1))

# Generated by 1.1.7.1 https://github.com/kyuridenamida/atcoder-tools
def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  # type: int
    print((solve(N)))

def test():
    import doctest
    doctest.testmod()

def __starting_point():
    #test()
    main()

__starting_point()

num = int(input())
total = 0

for n in range(num+1):
    total = total + n

print(total)

#1≦N≦100
a = input()
#print(type(a))
b = int(a)
#print(type(b))
c=0

for i in range(1,b+1):
	c = c + i
print(c)


n = int(input())


def factorial(i: int):
    if i == 1:
        return 1
    else:
        return i + factorial(i - 1)


print((factorial(n)))


n = int(input())
ans = 0
for i in range(1, n + 1):
    ans += i

print(ans)


N = int(input())
ans = 0

for i in range(N):
    ans += i + 1

print(ans)

N = int(input())
a = 0
for i in range(1,N + 1):
    a =i + a
print(a)

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

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


N = input()

val = int(N) + 1
s = 0

for i in range(val):
    s += i

print(s)

n = int(input())
sum = 0
for i in range(1, n+1):
    sum += i
print(sum)


n = int(input())

c = (1 + n) * n / 2

print(int(c))

a = int(input())
ans = 0
for i in range(a):
  ans += i+1
print(ans)

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


import math
print(sum(list(range(1,int(input())+1))))

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


N = int(input())

ans = 0
for i in range(1, N + 1):
    ans += i
print(ans)

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

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

def iroha():
    count = int(input())
    result = 0
    for i in range(count+1):
        result += i

    print(result)


def __starting_point():
    iroha()
__starting_point()

n = int(input())
sums = 0
for i in range(n+1):
    sums += i

print(sums)

print(sum([x for x in range(1, int(input())+1)]))

# Nの入力受付
N = int(input())
# 1～Nの合計を計算
SUM = 0
for i in range(N):
    SUM = SUM + i + 1
print(SUM)


n = int(input())
count = 0
while n > 0:
  count += n
  n -= 1
 
print(count)

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

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

N = int(input())

L = list(range(N+1))
print(sum(L))

sum = 0
for i in range(1,int(input())+1):
  sum += i
  
print(sum)

sum = 0
num = int(input())
for i in range(1, num+1):
    sum += i

print(sum)

number = int(input())

answer = 0
for i in range(1, number + 1):
    answer += i

print(answer)

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


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

n = int(input())
sum = 0
for i in range(n +1):
    sum += i

print(sum)


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

n = int(input())
total = 0
for i in range(1,n+1):
  total += i
print(total)


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


N = int(input())
doces = 0
count = N

while count > 0:
    doces += count
    count -= 1
print (doces)

n=int(input())
s=0
for i in range(1,n+1):
  s+=i
print(s)

# キャンディーとN人の子供イージー

N = int(input())

answer = N + N * (N - 1) // 2

if 1 <= N <= 100:
    print(answer)
elif N <= 0 or 100 < N:
    print('Out of range')

N = int(input())
ans = 0

for i in range(0, N + 1):
    ans += i
print(ans)

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

a = int(input())
result = 0
for i in range(a+1):
  result+=i
print(result)  

"""
ABC043 A キャンディーとN人の子供イージー
https://atcoder.jp/contests/abc043/tasks/abc043_a
"""

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


import math
N = int(input())

sum = math.floor((N * (1 + N))/2)

print(sum)

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

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


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

Candy = int(input())
ans = 0
 
for i in range(Candy):
    ans += i + 1
 
print(ans)

n = int(input())

s = 0
for i in range(n):
    s += i
print(s+n)

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

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

N=int(input())
s=0
for i in range(0,N+1):
    s=s+i
print(s)

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)

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

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

import math
n = int(input())

print(math.floor(n/2*(n+1)))

n = int(input())
x = 0
for i in range(1, n+1):
  x += i
print(x)

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

n = int(input())

print((n*(n+1)//2))


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


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(n*(n+1)/2)))



n = int(input())

c = 0
while n!=0:
    c += n
    n -= 1
print(c)

N=int(input())

x=int((N+1)*N/2)

print(x)

n=int(input())
memo=[0]*110
memo[1]=1
for i in range(2,105):
    memo[i]=memo[i-1]+i
print(memo[n])


n = int(input())
m = 0
for i in range(1,n+1):
    m += i

print(m)

N = int(input())
cnt = 0
for i in range(N+1):
  cnt += i
print(cnt)

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

n = int(input())

print(sum(range(n+1)))

n = int(input())

ans = 0

for i in range(1,n+1):
  ans += i
print(ans)

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

N=int(input())
k=0

for i in range(N+1):
    k +=i
    
print(k)

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

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

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

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

n = int(input())
a = 0
for i in range(n+1):
  a = a+i

print(a)

N=int(input())

print((1+N)*N//2)

N = int(input())

ans = 0

for i in range(N):
    ans += i + 1
print(ans)

n=int(input())

print(n*(n+1)//2)

def main():
    n = int(input())

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



def __starting_point():
    main()

__starting_point()

N = int(input())

sum = 0
for i in range(1,N+1):
    sum += i

print(sum)

N = int(input())
Sum = 0
for i in range(1, N + 1):
    Sum += i
print(Sum)

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

n = input()
cu = 0
cd = 0
for i in range(int(n)):
    cu+=1
    cd+=cu

print(cd)

N = int(input())
ans = 0
for i in range(N + 1):
  ans += i
print(ans)


print(sum(range(int(input())+1)))

print(sum(list(range(int(input())+1))))

# キャンディーとN人の子供イージー

N = int(input())

answer = N + N * (N - 1) // 2

print(answer)

n = int(input())
ans = 0
for i in range(1, n + 1):
    ans += i
print(ans)

ans = 0
a=int(input())
for i in range(a+1):
	ans+=i
print(ans)

N=int(input());num=0
for i in range(N):num+=i+1
print(num)