#include<iostream>
#include<cstdio>
#include<vector>
#include<queue>
#include<cmath>
#include<map>
#include<set>
#include<string>
#include<algorithm>
#include<functional>
using namespace std;
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define INF 1<<30
#define MP make_pair
#define mp make_pair
#define pb push_back
#define PB push_back
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define ll long long
#define ull unsigned long long

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	set<ll> an;
	ll N;cin>>N;
	N=(N&1) ? N: N/2;
	for(ll i=1;i<sqrt(N)+1;i++){
		if(N%i==0){
			an.insert(i);
			an.insert(N/i);
		}
	}
	ll sum=0;
	for(auto it:an) sum+=it;
	cout<<sum<<endl;
	 

}