//sum of n natural no.s

#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int n,s;
cout<<endl<<endl;
cout<<"*****************************************************************************";
cout<<endl<<endl;
cout<<"ENTER VALUE OF 'n'(where n=natural no. till where sum is needed)-";
cin>>n;
s=(n*(n+1))/2;
cout<<"SUM OF "<<n<<" NATURAL NO.s="<<s;
cout<<"\n*****************************************************************************";
getch();
return 0;
}