#include<stdio.h>
int main() {
int N;
scanf("%d", &N);
int sum = 0;
for(int i=1; i<=N; i++) sum += i;
printf("%d\n", sum);
}
#include <iostream>
using namespace std;
int main() {
int N;
scanf("%d", &N);
int sum = 0;
for(int i=1; i<=N; i++) sum += i;
printf("%d\n", sum);
}
import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int sum = 0;
for( int i=1; i<=n; i++ ) {
sum += i;
}
System.out.println(sum);
}
}
$sum += $_ for(1..<>);
printf("%s\n", $sum);
<?php
fscanf(STDIN,"%d",$N);
$sum = 0;
for( $i=1; $i<=$N; $i++ ) {
$sum += $i;
}
echo $sum;
n = int(input())
sum = 0
for i in range(1,n+1):
sum += i
print( sum )