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)
                }
        }
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
  int n;
  while(cin>>n){
    int ans = n+1;
    for(int i=1;i<n;++i)
      ans += i;
    cout<<ans<<endl;
  }
  return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
  int n, i, s;
  int a[1000];
  while(cin>>n){
  a[0]=2;
  for(i=1; i<n;i++){
    a[i]=a[i-1]+i+1;  
  }
  cout<<a[n-1];
  }
  return 0;  
}

C++: #include <bits/stdc++.h>
using namespace std;

using db = double;
using ll = long long;
using vi = vector <int>;
#define op operator
#define pb push_back

int main() {
	cout << fixed << setprecision(9);
	ios :: sync_with_stdio(0);

	for(int n; cin >> n; ) {
		cout << n * (n + 1) / 2 + 1 << '\n';
	}

	return 0;
}

C++: #include <cstdio>
#include <iostream>
using namespace std;
int main() {
	int n;
	while(cin >> n) {
		printf("%d\n", (1 + n * (n + 1) / 2));
	}
}

C++: #include <iostream>
#include <vector>

using namespace std;

typedef long long ll;

// int main(){
//     vector<ll> vec(10001);
//     vec[0] = 1;
//     for(int i=1;i<=10000;i++){
//         vec[i] = vec[i-1] + i;
//     }
//     int n;
//     while(cin >> n){
//         cout << vec[n] << endl;
//     }
//     return 0;
// }
int main(){
     int n;
     while(cin >> n){
         cout << n*(n+1)/2 +1 << endl;
     }
     return 0;
}

C++: #include <iostream>
using namespace std;

int main()
{
    int n;
    while (1) {
	cin >> n;
	if (cin.eof()) break;
        int ans = 1;
        for (int i = 1; i <= n; i++)
            ans += i;
        cout << ans << endl;
    }

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
  int n,a;
  while(cin >> n){
    a = 1;
    for(int i=1; i<=n; i++){
	a += i;
    }
  cout << a << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int main(){
	int n,a;
	while(cin>>n){
	a=1;
	for(int i=1;i<=n;i++)
		a+=i;
	cout<<a<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,j,k) for(int i=(int)j;i<(int)k;i++)
#define rrep()
#define Sort(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define vi vector<int>
#define INF (int)1e9
#define INFL 1e18
#define MOD 1000000007
#define pb push_back
#define MP make_pair
typedef long long int ll;
typedef std::pair<int,int> P;
int D=1;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};

using namespace std;

int main(){
    int n;
    while(cin>>n){
        int ans=0;
        rep(i,0,n+1)ans+=i;
        cout<<ans+1<<endl;
    }
    
    return 0;
}

C++: #include<iostream>
using namespace std;

int Calc( int x )
{
    if( x == 1 )
        return 2;
    
    return x + Calc( x - 1 );
}

int main()
{
    int n;

    while( cin >> n )
    {
        cout << Calc( n ) << endl;
    }
    return 0;
}

C++: #include <cstdio>
#include <utility>
#include <iostream>
#include <string>
#include <regex>
using namespace std;

#define gcu getchar_unlocked
#define ii inline int in
#define is inline bool scan
ii(int c) {
	int n = 0;
	bool minus = false; if (c == '-') minus = true, c = gcu();
	do {n = 10 * n + (c - '0'), c = gcu();} while (c >= '0');
	//return n; }
	return minus ? -n : n; }
ii() {return in(gcu());}
is(int &n){int c=gcu();return c==EOF?false:(n=in(c),true);}
is(char &c){c=gcu();gcu();return c!=EOF;}
is(string &s){int c;
	for(;;){c=gcu();if(c=='\n'||c==' ')return true;else if(c==EOF)return false;s+=c;}}
#undef ii
#define pcu putchar_unlocked
template <typename T>
void out(T n) {
	static char buf[20];
	char *p = buf;
	if(n < 0) pcu('-'), n *= -1;
	if (!n) *p++ = '0';
	else while (n) *p++ = n % 10 + '0', n /= 10;
	while (p != buf) pcu(*--p); }
void out(const char *s){while(*s)pcu(*s++);}
void out(char c){pcu(c);}
void out(string &s){for (char c: s) pcu(c);}
template <typename head, typename... tail>
void out(head&& h, tail&&... t){out(h);out(move(t)...);}
//template <typename T>
//void out(vector<T> &v){for(T &x:v)out(&x == &v[0]?"":" "),out(x);out('\n');}
#undef svo

int main() {
	for (int n; scan(n);)
		out((n * n + n + 2) / 2, '\n');
}

C++: #include <iostream>
#include <vector>

using namespace std;

typedef long long ll;
int main(){
    vector<ll> vec;
    vec.push_back(1);
    for(int i=1;i<=10000;i++){
        vec[i] = vec[i-1] + i;
    }
    int n;
    while(cin >> n){
        cout << vec[n] << endl;
    }
    return 0;
}

// int main(){
//      int n;
//      while(cin >> n){
//          cout << n*(n-1)/2 +1 << endl;
//      }
//      return 0;
//  }

C++: #include<iostream>
#include<string>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
#include<set>
#include<complex>
#include<map>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define all(in) in.begin(), in.end()
#define MAX 9999999
using namespace std;
typedef pair<int, int> pii;
int main(){
    int n;
    while (cin>>n) {
        vector<int>v(n);int i;
        for(i=0,v[0]=2;i<n;i++)if(i)v[i]+=v[i-1]+i+1;
        cout<<v[n-1]<<endl;
    }
}

C++: #include <iostream>
using namespace std;

int main(){
	int n;
	while(cin >> n){
		cout << (n * (n + 1) / 2 + 1) << endl;
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
int main(){

  int in;
  while(cin >> in!='\0'){
    int out=1;
    for(int i=1;i<=in;i++)
      out+=i;
    cout << out << endl;
  }
}

C++: #include <iostream>

int heimen(int nn){
	int a;
	a=((nn*nn)+nn+2)/2;
	return a;
}
using namespace std;

int main(){
	int n,ans;
	while(cin>>n){
		ans=heimen(n);
		cout<<ans<<endl;
	}
}

C++: #include<stdio.h>

int main(){

int N;
int s=1;
while(scanf("%d",&N)!=EOF){
for(int i=0;i<N;i++)
s+=i;
printf("%d\n",s);
s=1;
}
return 0;
}

C++: #include <iostream>
using namespace std;

int main(void) {
    int n;
    
    while(cin >> n) {
        int area = (n * n + n + 2) / 2;
        
        cout << area << endl;
    }
    
    return 0;
}

C++: 
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <stack>
#include <cctype>
#include <complex>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cassert>

using namespace std;


bool solve(){
	int n;
	while(cin>>n){
		int ans = 1;
		for(int i=1;i<=n;i++){
			ans += i;
		}
		cout<< ans<< endl;
	}
	return true;
}

int main(){
	cout.setf(ios::fixed);
	cout.precision(10);
	solve();
	return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<list>
#include<map>
#include<vector>
#include<algorithm>
#include<string.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) range(i,0,b)
#define debug(x) cout << x << endl;
using namespace std;

int main(){
    int n;
    int ans;
    while(cin >> n){
        ans = 2;
        rep(i,n){
            ans += (i + 1);
        }
        cout << ans - 1 << endl;
    }
}

C++: #include <iostream>
using namespace std ;

int main()
{
	int get ;
	while( cin >> get )
	{
		int sum = 1 ;
		for( int i = 1 ; i <= get ; i ++ )
		{
			sum += i ;
		}
		cout << (sum) << endl ;
	}
	return 0 ;
}

C++: #include <iostream>
#include <cstdio>

using namespace std;

int main()
{
  int N;
  while (scanf("%d ", &N) == 1)
    cout << (N + 1) * N / 2 + 1 << endl;
}