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

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

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

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

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

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

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

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

print(sum)

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

    print(result)


if __name__ == "__main__":
    iroha()

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

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



if __name__ == '__main__':
    main()

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

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

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

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

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

Solution (Python):
"""
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)

Solution (Python):
import math
from datetime import date

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

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

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

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

Solution (Python):

N = int(input())

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

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

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

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

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

print(cd)

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

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

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

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

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

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

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

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

print(m)

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

print(sum)

Solution (Python):

import sys


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


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

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

if __name__ == '__main__':
    
    main()

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

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

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

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

print(answer)

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())
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+1)//2)

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

Solution (Python):
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)

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

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

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

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

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

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


if __name__ == "__main__":
    main()

Solution (Python):
import bisect,collections,copy,heapq,itertools,math,string
import sys
def S(): return sys.stdin.readline().rstrip()
def M(): return map(int,sys.stdin.readline().rstrip().split())
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())
N = I()
ans = 0
for i in range(1, N+1):
    ans += i
print(ans)

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

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

print(ans)

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


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


print(factorial(n))

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

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

print(x)

Solution (Python):
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("\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)
'''

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

ans = 0

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

Solution (Python):
import sys
def input(): return sys.stdin.readline().strip()

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

if __name__ == "__main__":
    main()

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

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

Solution (Python):
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)

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

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

Solution (Python):
a = 0

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

print(a)

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

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

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

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

Solution (Python):
import sys

readline = sys.stdin.readline
MOD = 10 ** 9 + 7
INF = float('INF')
sys.setrecursionlimit(10 ** 5)


def main():
    N = int(readline())
    print(N * (N + 1) // 2)


if __name__ == '__main__':
    main()

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

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

print(sums)

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

Solution (Python):


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')

Solution (Python):


N = int(input())

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

print(answer)

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

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

print(sum)

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

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

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

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())
i = 1
ls = []
for i in range(a + 1):
  ls.append(i)
print(sum(ls))

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(n):
    ans += i+1
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())

print(sum(range(1, N + 1)))

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

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

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

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

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

print(ans)

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

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


i = 1
result = 0;

while i <= input_num:
    result = result + i
    i = i + 1

print(result)

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 + 1)) // 2)

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

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

print(answer)

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

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

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

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

candy = 0

for i in range(child + 1):
    candy = candy + i

print(candy)

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

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

Solution (Python):



x=input()
i=int(x)
sum=0

while i>0:
    sum=sum+i
    i=i-1
if i==0 :
    print(sum)

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

total = N * ( N + 1) // 2

print(total)

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

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

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

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

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

Solution (Python):







N = int(input())



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

print(answer)

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

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

print(a)

Solution (Python):



N = int(input())



print(sum(range(1,N + 1)))

Solution (Python):
a=int(input())
s=0

while a>0:
  s+=a
  a-=1
  
print(s)

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

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

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

print(answer)

Solution (Python):


N = int(input())



total = N * ( N + 1) // 2

print(total)

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

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

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

print(x)

Solution (Python):

N=int(input())
1<=int(N)<=100

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

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())

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

print(x)

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

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

i = 1
SUM = 0

while i <= N:
    SUM += i
    i += 1

print(SUM)

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())

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

print(x)

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

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

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

print(answer)

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

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

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

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



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

Solution (Python):
N = input()
s = 0
i = 1
while i <= int(N):
	s = s + i
	i = i + 1
print(s)

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

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

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

Solution (Python):





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

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

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

print(sum_num)

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

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

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

ame = 0

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

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

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

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

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

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

t = 0

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

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

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

candy = 0

for i in range(number):
    candy_add = i + 1
    candy = candy + candy_add

print(candy)

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

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

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

print(candy)

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

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

print(answer)

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

Solution (Python):




N = int(input())


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


print(x)

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

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

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

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

print(sum)

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

wa = 0
for i in range(num):
    wa += i+1
    
print(wa)

Solution (Python):

N = int(input())


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


print(x)

Solution (Python):

N = int(input())


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


print(answer)

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

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

print(answer)

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

x=0

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

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

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

Solution (Python):

N = int(input())

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

Solution (Python):




N = int ( input () )

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

print (answer)

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

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

Solution (Python):

n = int(input())

result = 0

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

print(result)

Solution (Python):



N = int(input())

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

Solution (Python):





n = int(input())


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

print(answer)

Solution (Python):

N = int(input())
if 1 <= N & N <= 100:
    result = 0
    for i in range(N):
        count = N - i
        result += count
        if count == 1:
            print(result)

Solution (Python):





child = int(input())

answer = int(child * (child + 1) / 2)

print(answer)

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

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

print(answer)

Solution (Python):







N = int(input())


answer = 0




while 1 <= N <= 100:
    answer = answer + N
    N = N - 1

print(answer)

Solution (Python):



n = int(input())


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


print(int(candy))

Solution (Python):



n = int(input())


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


print(int(candy))

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

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

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

Solution (Python):










N=int(input())

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

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

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

Solution (Python):





N = int(input())


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

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

sum_candy = n*(n+1)/2

print(int(sum_candy))

Solution (Python):

N = int(input())


Childrencnt = 1
Candysum = 0
for Childrencnt in range(1, N+1):
    Candysum = Candysum + Childrencnt


else:
    print(Candysum)

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

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

print(candy)

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





a = N+1
b = N

print(int( a * b * 0.5 ))

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

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

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

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

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

Solution (Python):






input_num = int(input())


i = 1
result = 0;

while i <= input_num:
    result = result + i
    i = i + 1

print(result)

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

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

result = 0;
for n in range(N + 1):
    result += n
print(result)

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

if N % 2 == 0:
    result = (N / 2) * (1 + N)
else:
    result = ((N - 1) / 2) * N + N

print(int(result))

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

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

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

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

Solution (Python):


N = int(input()) 

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

print(candy)

Solution (Python):

N = int(input())

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

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

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

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

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

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

print(answer)

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

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

print(answer)

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

Solution (Python):

N = int(input())


total = 0


while N > 0:
    total += N
    N -= 1
print(total)

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

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

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

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

print(answer)

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

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

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

Solution (Python):

child_num = int(input())

candy_num = int((child_num**2 + child_num) / 2)
print(candy_num)

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())


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


print(total)

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

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

print(a)

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

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

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

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

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

row = list(range(1, N+1, 1))

total_candy = sum(row)
print(total_candy)

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

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

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

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

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

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

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

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

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

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

print(answer)

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

Solution (Python):


N = int(input())

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

print(answer)

Solution (Python):




child_number = int(input())



answer = int(child_number * (child_number + 1) / 2)


print(answer)

Solution (Python):
num_of_children = int(input())
total_candy = 0

for i in range(1, num_of_children +1):
    total_candy = total_candy + i

print(total_candy)

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

Solution (Python):
N = int(input())
answer = 0
while not N == 0 :
    answer += N
    N -= 1
else :
    print(answer)

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

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

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

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

print(x)

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

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

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

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

i=1
j=0
while i < N+1:
    j += i
    i += 1
print(j)

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

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

Solution (Python):
n = int(input())
r = 0
while n!=0:
  r = r+n
  n-=1
print(r)

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

sum=0
for num in range(1, child+1):
    sum= sum + num
print(sum)

Solution (Python):

def main():
    n = int(input())
    cnt = 0

    for i in range(1, n+1):
        cnt += i
    else:
        print(cnt)
 
    
if __name__ ==  "__main__":
    main()

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

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

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):
def main():
    N = int(input())
    total = [i for i in range(1, N+1)]
    print(sum(total))


if __name__ == "__main__":
    main()

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

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

total=0

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

print(total)

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

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

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

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

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

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

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

total = 0

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

print(total)

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(1,n+1):
    ans += i
print(ans)

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

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())

ans = int(n * (1 + n) / 2)
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())
a = 0
b = 0
for i in range(n):
    a += 1
    b += a
print(b)

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

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

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

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

print(sum)

Solution (Python):

N = int(input())
s = 0

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

print(s)

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

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

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

Solution (Python):
N = int(input())
s = 0
i = 1
while i <= N:
  s = s + i
  i += 1
print(s)

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

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):
from sys  import stdin,stdout

import bisect

import math

def st():
    return list(stdin.readline().strip())

def inp():
    return int(stdin.readline())

def li():
    return list(map(int,stdin.readline().split()))

def mp():
    return map(int,stdin.readline().split())

def pr(n):
    stdout.write(str(n)+"\n")

def soe(limit):
    l=[1]*(limit+1)
    prime=[]
    for i in range(2,limit+1):
        if l[i]:
            for j in range(i*i,limit+1,i):
                l[j]=0

    for i in range(2,limit+1):
        if l[i]:
            prime.append(i)
    return prime

def segsoe(low,high):
    limit=int(high**0.5)+1
    prime=soe(limit)
    n=high-low+1
    l=[0]*(n+1)
    for i in range(len(prime)):
        lowlimit=(low//prime[i])*prime[i]
        if lowlimit<low:
            lowlimit+=prime[i]
        if lowlimit==prime[i]:
            lowlimit+=prime[i]
        for j in range(lowlimit,high+1,prime[i]):
            l[j-low]=1
    for i in range(low,high+1):
        if not l[i-low]:
            if i!=1:
                print(i)
                
def gcd(a,b):
    while b:
        a=a%b
        b,a=a,b
    return a

def power(a,n):
    r=1
    while n:
        if n&1:
            r=(r*a)
        a*=a
        n=n>>1
    return r

def check(n,s):
    v=str(n)
    for i in v:
        if i in s:
            return False
    return True
    

    
def solve():
    n=inp()
    a=n*(n+1)//2
    pr(a)

        
        

for _ in range(1):
    solve()

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

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

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

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

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

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

Solution (Python):
x = int(input())
out=[]
for i in range(0,x):
    out.append(i+1)
print(sum(out))

Solution (Python):
import math
import collections
import fractions
import itertools
import functools
import operator

def solve():
    n = int(input())
    print((n*(n+1))//2)
    return 0

if __name__ == "__main__":
    solve()

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

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

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

Solution (Python):
n=int(input())
i=0
while n > 0:
   i+=n
   n-=1
print(i)

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

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

Solution (Python):
n = int(input())
a = 0
while n > 0:
    a += n
    n -= 1
print(a)

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

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

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

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

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

r = 0

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

print(r)

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

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

mylist = 0
for num in range(n+1):
    mylist = mylist + num
print(mylist)

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

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

Solution (Python):


def main():

    N = int(input())
    ans = 0

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

    print(ans)

if __name__ == "__main__":
    main()

Solution (Python):
import sys
def I(): return int(sys.stdin.readline().rstrip())

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