#include <stdio.h>

int main()
{
	int intN,intCounter, flag;
	unsigned long int ulngSum;
	char ch ;

	do{
		do{
			flag=0;
			printf("Enter a number (0<n<30000):");
			scanf("%d", &intN);
			if((intN <=0) || (intN > 30000))
			flag = 1;
				}while(flag);

				ulngSum=0;

				for(intCounter = 1; intCounter<= intN; intCounter++)
				{
					ulngSum=ulngSum + intCounter;

					}

					printf("Required sum is :%lu\n", ulngSum);
					printf("do you want to continue? (Y/N) : \n");
					scanf(" %c", &ch);


			}while ((ch=='y') || (ch=='Y'));

			printf("Thank you.\n");

		return 0;
		}