# include<iostream>
using namespace std;
int sum(int n)
{
int i,sum=0;
for(i=1;i<=n;i++)
sum+=i;
return sum;
}
int main()
{
int n;
cout<<"Enter the number of numbers to find the sum:";
cin>>n;
cout<<"The sum of first "<<n<<" natural numbers is:<< sum(n);
}