#include<stdio.h>
#include<conio.h>
void main()
{
  int n,sum=0,i=1;
  clrscr();
  printf("enter the value of n\n");
  scanf("%d",&n);
  do
  {
    sum+=i;
    i++;
  }  while(i<=n);
  printf("\nsum=%d",sum);
  getch();
}