// Simple C++ program to
// find sum of all divisors
// of a natural number
#include<bits/stdc++.h>
using namespace std;
// Function to calculate sum of all
//divisors of a given number
int divSum(int n)
{
if(n == 1)
return 1;
// Sum of divisors
int result = 0;
// find all divisors which divides 'num'
for (int i = 2; i <= sqrt(n); i++)
{
// if 'i' is divisor of 'n'
if (n % i == 0)
{
// if both divisors are same
// then add it once else add
// both
if (i == (n / i))
result += i;
else
result += (i + n/i);
}
}
// Add 1 and n to result as above loop
// considers proper divisors greater
// than 1.
return (result + n + 1);
}
// Driver program to run the case
int main()
{
int n = 30;
cout << divSum(n);
return 0;
}