Problem:
 Score : 100 points    Problem Statement 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 1 3      Sample Output 1 6  The answer is 1+2+3=6 .       Sample Input 2 10      Sample Output 2 55  The sum of the integers from 1 to 10 is 55 .       Sample Input 3 1      Sample Output 3 1  Only one child. The answer is 1 in this case.

Solution (Python):
def solve():
    n = int(input())
    print((n+1)*n//2)

if __name__ == '__main__':
    solve()

Solution (Python):

n = int(input())

result = 0
for i in range(n):
  result += i+1

print(result)

Solution (Python):
n = input()
print((n*(n+1))//2)

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

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

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

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

Solution (Python):
n = int(input())

print(sum([i for i in range(1,n+1)]))

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

Solution (Python):
def check(n):
    return sum(range(1, n + 1))


def main():
    N = int(input())
    result = check(n=N)
    print(result)


if __name__ == '__main__':
    main()

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

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

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

Solution (Python):
n = int(input())

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

print(ans)

Solution (Python):
N = int(input())

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

print(sum)

Solution (Python):
N=int(input())
result = 0;
for i in range(1,N+1):
    result += i
        
print(result)

Solution (Python):
n = int(input())
print(sum([i+1 for i in range(n)]))

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

Solution (Python):
n=int(input())

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

Solution (Python):
n = int(input())





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

Solution (Python):
n = int(input())
if n == 1:
    print(1)
else:
    l = list(range(1, n + 1))
    print(sum(l))

Solution (Python):
n = int(input())

sum = 0

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

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

Solution (Python):
N=int(input())

print('{:.0f}'.format((1+N)*N/2))

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

Solution (Python):
if __name__ == "__main__":
    n = int(input())
    print(n * (n + 1)//2)

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

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

Solution (Python):
N = int(input())

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

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

Solution (Python):
N = int(input())
print(sum(range(N+1)))

Solution (Python):
n=int(input())
a=int(n*(n+1)/2)
print(a)

Solution (Python):
n =int(input())
l=[1]
for i in range(1,n):
  a = i +1
  l.append(a)
print(sum(l))

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

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

Solution (Python):
N = int(input())

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

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

Solution (Python):
count = 0
for i in range(int(input()) + 1):
  if i == 0:
    continue
  count += i
print(count)

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

Solution (Python):
print(sum([i for i in range(1, int(input())+1)]))

Solution (Python):
N = int(input())
total = 0
for i in range(1, N + 1):
  total += i

print(total)

Solution (Python):
a = int(input())

sum=0

for i in range(a+1):
    sum += i

print(sum)

Solution (Python):
n = int(input())
print(sum([a for a in range(1,n+1)]))

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

Solution (Python):
n = input()
result = 0

for i in range(int(n)):
  result += i+1

print(result)

Solution (Python):
import sys
N = input()
sum=0

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

print(sum)

Solution (Python):
n = int(input())

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

print(ans)

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

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

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

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    n = int(input().rstrip('\n'))
    t = 0
    for i in range(n):
        t += (i + 1)
    print(t)


if __name__ == '__main__':
    slove()

Solution (Python):


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

print(candy)

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

Solution (Python):
ninnzuu = int(input()) + 1
goukei = 0

for i in range(ninnzuu):
    goukei = goukei + i
print(str(goukei))

Solution (Python):
import sys

input = sys.stdin.readline


def main():
    n = int(input())
    print(sum(range(1, n + 1)))


if __name__ == "__main__":
    main()

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

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

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

Solution (Python):
v=0
for k in range(int(input())):
    i = k + 1 
    v += i
print(v)

Solution (Python):
n = int(input())

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

Solution (Python):
N = int(input())

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

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

Solution (Python):
N=int(input())
S=(N+1)*N//2
print(S)

Solution (Python):
N=int(input())
S=(N+1)*N//2
print(S)

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

Solution (Python):

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

Solution (Python):

N = input()

list_num = list(range(1,int(N)+1))

sum_list = sum(list_num)

print(sum_list)

Solution (Python):
from sys import stdin

count = 1
n = int(stdin.readline().rstrip())
s = 0

for i in range(n):
    s += count
    count += 1

print(s)

Solution (Python):
num=int(input())
candy=0
ans=0
for i in range(num):
  candy+=1
  ans+=candy
print(ans)

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

Solution (Python):
n = int(input())
c = 0
for i in range(n+1):
  c += i
print(c)

Solution (Python):
n = int(input())
k = 0

for i in range(n + 1):
  k +=  i
  i + 1

print(k)

Solution (Python):
import sys
sys.setrecursionlimit(2147483647)
INF=float("inf")
MOD=10**9+7
input=lambda :sys.stdin.readline().rstrip()
def resolve():
    n=int(input())
    print(n*(n+1)//2)
resolve()

Solution (Python):


n = int(input())

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

print(ans)

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

Solution (Python):
child = int(input())
sum = 0
for i in range(child+1):
  sum += i
print(sum)

Solution (Python):
INT = lambda: int(input())
INTM = lambda: map(int,input().split())
STR = lambda: str(input())
LIST = lambda: list(map(int,input().split()))
def do():
    N = INT()
    print(int(N*(N+1)/2))
if __name__ == '__main__':
    do()

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

Solution (Python):


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

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

Solution (Python):
N=int(input())
def sum(N):
    if N==1:
        return 1
    else:
        return N+sum(N-1)
print(sum(N))

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

Solution (Python):
print((lambda x: x*(x+1)//2)(int(input())))

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

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

Solution (Python):
N = int(input())
sigma = 0

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

print(sigma)

Solution (Python):
print(sum([i+1 for i in range(int(input()))]))

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

Solution (Python):
N = int(input())
candies = [n for n in range(1, N+1)]
print(sum(candies))

Solution (Python):

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

Solution (Python):
def resolve():
    n = int(input())
    print(n * (n + 1) // 2)


if __name__ == "__main__":
    resolve()

Solution (Python):
N=int(input())

print(int(0.5*N*(N+1)))

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

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

Solution (Python):
N = int(input())
a = [i for i in range(N+1)]
ans = sum(a)
print(ans)

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

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

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

Solution (Python):
import sys
input = sys.stdin.readline

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

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


if __name__ == "__main__":
    main()

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

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

Solution (Python):

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

Solution (Python):
a = int(input())
b = a * (a + 1) / 2
print(int(b))

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

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

Solution (Python):
A = int(input())
result = 0
for i in range(A):
    result += i+1

print(result)

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

Solution (Python):
n = int(input())
print(sum(range(n+1)))

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

Solution (Python):
N  = int(input())

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

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

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

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

Solution (Python):
N=int(input())
X=(N*(N+1))//2
print(X)

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

Solution (Python):
N=int(input())
a=N//2
b=N%2
if b==0:
	x=(N+1)*a
else:
	x=(N+1)*a+a+1
print(x)

Solution (Python):
n = int(input())
l = list(range(1, n+1))
print(sum(l))

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

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

Solution (Python):
N=int(input());print(N*(N+1)//2)

Solution (Python):
n=int(input());print(n*-~n//2)

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

Solution (Python):
N = int(input())

res = 0

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

print(res)

Solution (Python):
n = int(input())
ans = sum(range(1,n+1))
print(ans)

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

Solution (Python):
i = int(input())
k = 0
for j in range(i + 1):
  k = k + j
print(k)

Solution (Python):
print(sum([i for i in range(int(input()) + 1)]))

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

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

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

Solution (Python):
print(sum(range(1,int(input())+1)))

Solution (Python):
N = int(input())
list_N = [ x for x in range(1, N+1) ]
print( sum(list_N) )

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

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

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

Solution (Python):
n=int(input());print(n*-~n//2)

Solution (Python):
n = int(input())
count = 0
if 1 <= n <= 100:
    for i in range(1,n+1):
        count += i
    print(count)
else:
    print('hoge!')

Solution (Python):
a = int(input())
l=[]
for i in range(a):
        l.append(i+1)
print(sum(l))

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

Solution (Python):
print(sum(range(int(input())+1)))

Solution (Python):
n = int(input())
k=0
for i in range (n):
    k +=i+1
print(k)

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

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

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

Solution (Python):
n = int(input())
if n%2 == 0:
  print((n+1)*n//2)
else:
  print((n+1)*(n//2)+n//2+1)

Solution (Python):
kosu = [0]*100
kosu[0] = 1
for i in range(99):
    kosu[i+1] = kosu[i] + i+2
print(kosu[int(input())-1])

Solution (Python):
N = int(input())
n_list = [x for x in range(1, N+1)]
print(sum(n_list))

Solution (Python):
import sys

stdin = sys.stdin
ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline()

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

Solution (Python):
N = int(input())

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

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

Solution (Python):
def main():
    n = int(input())
    print(int((n * (n + 1)) / 2))
if __name__ == '__main__':
    main()

Solution (Python):
def main():
    n = int(input())
    print(int((n * (n + 1)) / 2))
if __name__ == '__main__':
    main()

Solution (Python):
def main():
  n = int(raw_input())
  result = 0
  for x in xrange(n):
    result += x + 1
  print result

main()

Solution (Python):
N = int(input())
print(sum(range(1,N+1)))

Solution (Python):
n = int(input())

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

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

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

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

Solution (Python):
n = int(input())

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

print(total)

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

Solution (Python):
print(sum(range(1, int(input()) + 1)))

Solution (Python):

def main():

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

if __name__ == '__main__':
    print(main())

Solution (Python):
print(sum(range(int(input()) + 1)))

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

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

Solution (Python):
n=int(input())

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

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

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

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

Solution (Python):
print(sum(range(1, int(input())+1)))

Solution (Python):
print(sum(range(int(input()) + 1)))

Solution (Python):
print(sum(range(1,int(input())+1)))

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

Solution (Python):

import sys
import copy
import collections
from bisect import bisect_left
from bisect import bisect_right
from collections import defaultdict
from heapq import heappop, heappush, heapify
import math
import itertools
import random
 




 
INF = float('inf')
def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))
 
def main():
    N = inputInt()
    ans = 0
    for i in range(1,N+1):
        ans += i
    
    print(ans)
    
if __name__ == "__main__":
	main()

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

Solution (Python):
n=int(input())

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

print(ans)

Solution (Python):
n=int(input());print(n*-~n//2)

Solution (Python):
n = int(input())

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

Solution (Python):
N = int(input())
num_list = []

for i in range(N):
  num_list.append(i + 1)

print(sum(num_list))

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

Solution (Python):
def gokei(x):
  if x<=0:
    return 0
  p = x + gokei(x-1)
  return p

n = int(input())
print(gokei(n))

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

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

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

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

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

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

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

Solution (Python):
n = int(input())
sum = n
for i in range(n):
    sum += i
print(sum)

Solution (Python):
n = int(input())

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

Solution (Python):
a=int(input())
b=0
for x in range(1,a+1):
  b+=x
print(b)

Solution (Python):
print(sum(list(range(1, int(input()) + 1))))

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

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

Solution (Python):
count = 0
for i in range(int(input())):
  count += i+1
print(count)

Solution (Python):
s=0
for i in range(int(input())):
    s +=i+1
print(s)

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

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

Solution (Python):
n=int(input())

m=n-(n-1)
print(int((n/2)*(n+m)))

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

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

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

Solution (Python):
N = int(input())
print(sum([i for i in range(N+1)]))

Solution (Python):
n=int(input())
print(int((n+1)*n*0.5))

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

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

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

Solution (Python):
N = int(input())
print((N // 2) * (N+1) + (N // 2) + 1 if N % 2 else (N // 2) * (N+1))

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

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

Solution (Python):
N = int(input()) 
b = N +1 
total = 0
for i in range(b): 
	total += i
print(total)

Solution (Python):

N = int(input())

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

Solution (Python):
print(sum([i + 1 for i in range(int(input()))]))

Solution (Python):
N=int(input())
n=0
for i in range(N+1):
    n+=i
print(n)

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

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

Solution (Python):
print(sum([i for i in range(int(input())+1)]))

Solution (Python):
N = int(input())

ans = 0

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

print(ans)

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

print(ans)

Solution (Python):
print(sum(range(int(input())+1)))

Solution (Python):
n = int(input())

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

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

Solution (Python):
N = int(input())
r = N*(N+1)//2
print(r)

Solution (Python):
N=int(input())

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

Solution (Python):
N=int(input())

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

Solution (Python):
def A_ChildrenandCandies():
    N = int(input())
    print(sum(range(N+1)))
    
if __name__ == "__main__":
    A_ChildrenandCandies()

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

Solution (Python):
n = int(input())

cnt= 0

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

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

Solution (Python):
n = int(input())
answer = 0
for i in range(1, n + 1):
  answer += i

print(answer)

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

Solution (Python):
n = int(input())
 
def add_me(now):
  return 1 if now == 1 else now + add_me(now - 1)
print(add_me(n))

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

Solution (Python):
n = int(input())

ans = sum([i for i in range(1, n + 1)])
print(ans)

Solution (Python):

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

print(count)

Solution (Python):
N = int(input())

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

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

Solution (Python):
print(sum(i for i in range(1, int(input())+1)))

Solution (Python):

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

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

Solution (Python):

import numpy as np

N = int(raw_input())

a = np.linspace(1, N, N)
print int(np.sum(a))

Solution (Python):
n = int(input())
a = n//2
if n%2 ==0:
    a+=0.5
    a*=n
    print(int(a))
else:
    a+=1
    print(a*n)

Solution (Python):


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

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

Solution (Python):
N = int(input())
temp=(1+N)*(N//2)
if N%2==0:
  print(temp)
else:
  print(temp+N//2+1)

Solution (Python):
n=int(input())

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

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

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

Solution (Python):
N=int(input())
n=0
for i in range(N+1):
    n+=i
print(n)

Solution (Python):
n = int(input())
nn = [x for x in range(1,n+1)]
print(sum(nn))

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

Solution (Python):
n = input()
x = int(n)
y = 0.5*x*(x+1)
print(int(y))

Solution (Python):
n=int(input())
print(sum(range(n+1)))

Solution (Python):
n=int(input())
print(sum(range(1,n+1)))

Solution (Python):
print(sum([(i + 1) for i in range(int(input()))]))

Solution (Python):



N = int(input())


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

Solution (Python):
n=int(input())
sum=n*(n+1)/2
print(int(sum))

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

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

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

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

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

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

Solution (Python):
N = raw_input()
ans = 0
for i in range(1,int(N)+1):
    ans += i
print ans

Solution (Python):
a = int(input())

b = 0

while a != 0:
  b = b + a
  a = a - 1

print(b)

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

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

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

Solution (Python):
n = int(input())
r = 0
for i in range(n+1):
  r += i
print(r)

Solution (Python):
n = int(input())

a = range(0, n+1)
b = sum(a)
print(b)

Solution (Python):
N = int(input())
sum_N = 0
for i in range(N+1):
    sum_N += i
print(sum_N)

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

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

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

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

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

print(sum)

Solution (Python):
n = int( input() )

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

Solution (Python):
n = int(input())

c = 1
ans = 0
for i in range(n):
    ans += c
    c += 1
    
print(ans)

Solution (Python):
N = int(input())
print(sum(range(N+1)))

Solution (Python):
N = int(input())
print(sum(range(N+1)))

Solution (Python):
cnt = int(input())
print(sum([i for i in range(1, cnt + 1)]))

Solution (Python):
cnt = int(input())
print(sum(list(map(lambda x: x, range(1, cnt + 1)))))

Solution (Python):
N = int(input())

ans = 0

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

Solution (Python):

child_num = int(input())

candy_num = child_num * (child_num+1) / 2

print(int(candy_num))

Solution (Python):
num = int(input())
ans = int(num * (num + 1) / 2)
print(ans)

Solution (Python):
n = int(input())

res = 0
for i in range(n):
    res += (i+1)

print(res)

Solution (Python):

import sys
sys.setrecursionlimit(300000)


def solve(N: int):
    ret = (1 + N) * N // 2
    print(ret)
    return


def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    solve(N)

if __name__ == '__main__':
    main()

Solution (Python):
print((lambda x: int(x)*(int(x)+1)//2)(   input()))

Solution (Python):
N=int(input())

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

print(count)

Solution (Python):
N=int(input())

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

Solution (Python):

import sys


def main():
    num = int(input())
    ans = 0
    for i in range(num):
        ans += i + 1

    print(ans)
if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())

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

print(ans)

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

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

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

Solution (Python):
n = int(input())
print(sum(range(n+1)))

Solution (Python):
N=int(input())

ans=0

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

print(ans)

Solution (Python):
print(sum([j for j in range(int(input())+1)]))

Solution (Python):
print(sum([j for j in range(int(input())+1)]))

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

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

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

Solution (Python):
x = int(input())
a=0
for i in range(x):
    a += i+1 
print(a)

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

Solution (Python):
n = int(input())

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

Solution (Python):
def main():
    N = int(input())
    ans = 0
    for i in range(1, N + 1):
        ans += i
    print(ans)
if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())
kazu = 0
for i in range(n + 1):
  kazu += i
print(kazu)

Solution (Python):
n = int(input())
ans = 0
for i in range(1, n+1):
  ans += i
print("{}".format(ans))

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

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

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

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

Solution (Python):

import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

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

Solution (Python):

import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

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

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

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

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

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

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

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

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

Solution (Python):
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd
 
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def S_MAP(): return map(str, input().split())
def LIST(): return list(map(int, input().split()))
def S_LIST(): return list(map(str, input().split()))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N = INT()

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

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

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

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

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

Solution (Python):

N = int(input())


ans = 0

for i in range(N):

    i += 1
    ans += i

print (ans)

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

Solution (Python):
N = int(input())

SUM = 0

for n in range(1,N + 1):
    
    SUM = SUM + n

print(SUM)

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

Solution (Python):
n = int(input())
count = 0
for i in range(n+1):
  count = count + i
print(count)

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

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

Solution (Python):
sum = 0
num = int(input())
for a in range(num+1):
    sum += a
print(sum)

Solution (Python):
a = int(input())
print(sum([i+1 for i in range(a)]))

Solution (Python):
N = int(input())

def Counter(n):
    if n <= 0:
        return n
    return n + Counter(n-1)
    

print(Counter(N))

Solution (Python):
N = int(input())

C = 0

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

print(C)

Solution (Python):
sum = 0
n = int(input())

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

print(sum)

Solution (Python):
N = int(input())

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

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

Solution (Python):

from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
bisect_left = bisect.bisect_left
bisect_right = bisect.bisect_right
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def A():
    a = II()
    ans = 0
    for i in range(a + 1):
        ans += i
    print(ans)
    return


def B():
    return


def C():
    return


def D():
    return


def E():
    return


def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    A()

Solution (Python):
n = int(input())
num = list(range(1,n+1))
print(sum(num))

Solution (Python):
print(sum(list(range(int(input())+1))))

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

Solution (Python):
N = int(input())
n = 0

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

Solution (Python):
N = int(input())
n = 0

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

Solution (Python):
N = int(input())

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

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

Solution (Python):


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

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

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

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

Solution (Python):


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

if __name__ == "__main__":
    solve()

Solution (Python):
n=int(input())
print(int((n**2+n)/2))