1 import java.util.Scanner; 2  3 public class P1068 4 { 5     public static void main(String args[]) 6     { 7         try (Scanner cin = new Scanner(System.in)) 8         { 9             while (cin.hasNext())10             {11                 int n = cin.nextInt();12                 int result = 0;13                 if (n < 1)14                     for (int i = n; i <= 1; i++)15                         result += i;16                 else17                     for (int i = 1; i <= n; i++)18                         result += i;19                 System.out.println(result);20             }21         }22     }23 }