#include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<utility>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<functional>
#include<math.h>
#include<random>
#include <bitset>
using namespace std;
#define N (1000000000+7)
//#define N 998244353
#define INF 1e16
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> Q;

const int inf = (int)1e9; 

ll gcd(ll a, ll b) {
	if (b > a) {
		ll tmp = b;
		b = a;
		a = tmp;
	}
	if (a%b == 0)return b;
	else return gcd(b, a%b);
}


int main(void){
    ll n;
    cin>>n;
    if((n-1)%2==0){
        ll ans = 0;
        for(ll i=1;i*i<=n;i++){
            if(n%i==0){
                ll t = n/i;
                ans+=t;
                if(t!=i)ans+=i;
            }
        }
        cout<<ans<<endl;
    }
    else{
        n = n/2;
        ll ans = 0;
        for(ll i=1;i*i<=n;i++){
            if(n%i==0){
                ll t = n/i;
                ans+=t;
                if(t!=i)ans+=i;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}