Go: package main

import (
        "fmt"
)

func main() {
        var num int
        for {
                _, err := fmt.Scan(&num)
                if err != nil {
                        break
                } else {
                        fmt.Printf("%d\n", (num*num+num+2)/2)
                }
        }
}

Python: while True:
    try:
        a = int(input())
        print(((a * a) + a + 2) / 2)
    except EOFError:
        break

Python: while True:
    try:
        n = int(raw_input())                                                                                                                                                                                 

        print (a**2+a+2)/2

    except EOFError: break

Python: while True :
    try :
        n = int(input())
    except EOFError :
        break
    
    m = n*(n+1)//2 + 1
    print(m)

Python: while 1:
    try:
        n = int(input())
    except:break
    ans = (0.5 * n * n) + (0.5 * n) + 1        
    print(round(ans))

Python: import sys

for line in sys.stdin:
  try:
    n = int(line)
    print((n**2 + n + 2) // 2)
  except:
    break

Python: while True:
    try:
        n = int(input())
    except:
        break
    ans = 2
    for i in range(2, n + 1):
        ans += i
    print(ans)

Python: import sys
for i in sys.stdin.readlines():
    a = 2
    for i2 in range(2,int(i)+1):
        a += i2
    print(a)

Python: while True:
    try:
        a = int(raw_input())                                                                                                                                                                                 

        print (a**2+a+2)/2

    except EOFError: break

Python: while 1:
    try:n=int(input())
    except:break
    print((n*n+n+2)//2)

Python: import sys
sys.setrecursionlimit(100000)

while(1):
    try:
        n = int(input())
        print(int((n**2+n+2)/2))
    except EOFError:
        break

Python: import sys
for n in map(int, sys.stdin):
    print(n*(n+1)//2+1)

Python: # Aizu Problem 0057: Number of Area
#
import sys, math, os, bisect

# read input:
PYDEV = os.environ.get('PYDEV')
if PYDEV=="True":
    sys.stdin = open("sample-input.txt", "rt")


for line in sys.stdin:
    n = int(line)
    print(1 + n * (n + 1) // 2)

Python: import sys
lc=lambda n:int((n**2+n+2)/2)
[print(i) for i in [lc(int(j)) for j in sys.stdin]]

Python: while True:
    try:
        a = int(input())
        print(str(((a * a) + a + 2) / 2))
    except EOFError:
        break

Python: #! /usr/bin/python
# -*- coding: utf-8 -*-

def main():
    # input
    while(True):
        try:
            data = int(raw_input())
            print(countArea(data))
        except EOFError:
            break

def countArea(n):
    ans = 2
    while(n > 1):
        ans = ans + n
        n -= 1

    return ans

if __name__=='__main__':
    main()

Python: while 1:
    try:
        n=int(input())
        print(int(n*(n+1)/2)+1)
    except:break

Python: while True:
    try:
        n = int(input())
        print((1+n)*n//2 + 1)
    except:
        break

Python: import sys


def solve(n):
  if n == 0:
    return 1
  else:
    return n + solve(n - 1)


for line in sys.stdin:
  try:
    n = int(line)
    print(solve(n))
  except:
    break

Python: while(True):
    try: n = int(input())
    except: break
    print(1+sum([i+1 for i in range(n)]))

Python: while 1:
    try:
        n = int(input())
    except:
        break

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

Python: while True:
    try:
        N = int(input())
    except EOFError:
        break
    print(1 + sum(range(N + 1)))

Python: while True:
    try:
        n = int(input())
        ans = 2 + (n + 2)*(n - 1) / 2
        print(int(ans))
    except EOFError:
        break

Python: import sys
for i in sys.stdin:
    print(int(i)*(int(i)+1)//2+1)

Python: while True:
    try:
        l= int(input())
    except:
        break
    print((l**2+l+2)//2)

Python: while True:
	try:
		n=int(input())
		a=2
		d=2
		for i in range(n-1):
			a+=d
			d+=1
		print(a)
	except EOFError:
		break

Python: import sys
for line in sys.stdin.readlines():
  n = int(line)
  i = (1+n)*n//2+1
  print(i)

Python: while True:
    try:
        n = int(input())
    except:
        break

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

    print(sum)

Python: # -*- coding: utf-8 -*-

import sys

for line in sys.stdin:
    n = int(line)
    print (n*n+n+2)/2

Python: #! /usr/bin/python
# -*- coding: utf-8 -*-

def main():
    # input
    while(True):
        try:
            data = int(raw_input())
            print(countArea(data))
        except EOFError:
            break

def countArea(n):
    if n == 1:
        return 2
    else:
        return countArea(n-1) + n
        
if __name__=='__main__':
    main()

Python: while True:
    try:
        n = int(input())
    except:
        break
    print(n * (n + 1) // 2 + 1)

Python: while True:
  try:
    n = int(input())
    print(1 + n * (n + 1) // 2)

  except EOFError:
    break

Python: while True:
    try:
        n=int(input())
    except:
        break
    print(n * (n + 1) // 2 + 1)

Python: import sys

for s in sys.stdin:
    n = int(s)
    print (n * n + n + 2) / 2

Python: # AOJ 0057 The Number of Area
# Python3 2018.6.16 bal4u

while True:
	try: n= int(input())
	except: break
	print(1+n*(n+1)//2)

Python: 
def search(n):
    return (1+n*(n+1)//2)

while True:
    try:
        n=int(input())
    except:
        break
    #print(count(n))
    print(search(n))

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import (division, absolute_import, print_function,
                        unicode_literals)
from sys import stdin

L = [1]
for i in xrange(1, 10001):
    L.append(i + L[-1])

for line in stdin:
    n = int(line)
    print(L[n])

Python: a = [1]
for i in range(1, 10002):
    a.append(a[i-1]+i)
while True:
    try:
        print(a[int(input())])
    except:
        break

Python: # -*- coding:utf-8 -*-

while True:
	try:
		n = int(raw_input())
		print (n * n + n + 2) / 2
	except:
		break