#include<iostream>
using namespace std;
int main()
{
int b,c=0;
cin>>b;
for(int i=0;i<=b;i++){
c+=i;}
if(b<0){
for(int a=0;a>=b;a--){
c+=a;
}c=c+1;}
cout<<c;
return 0;
}


I WROTE OWN EXAMPLES AND IT PASSED ALL OF THEM!!!

Edited by author 11.03.2009 10:39

Try 0 as input, and speak not so loud, please ;)