#include <bits/stdc++.h>
using namespace std;
//#define int long long
#define FOR(i, s, n) for (int i = (s); i < (int)(n); i++)
#define RFOR(i, s, n) for (int i = (n) - 1; i >= (int)(s); i--)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define ALL(a) a.begin(), a.end()
constexpr long long INF = 1e18;
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a=b;return true;}return false;}

signed main(){
	int N;
	cin >> N;
	int sum = 0;
	for(int j = 1;j * j <= N;j++){
		if(N%j)continue;
		sum += j;
		if(j != N/j)sum += N/j;
	}
	cout << sum << endl;
}