#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

// long version
long long int GCD(long long int x, long long int y){
    if(x>y){
        long long int swap = x;
        x = y;
        y = swap;
    }
    while(true){
        if(y%x==0){
            return x;
        }else{
            long long int amari = y%x;
            y = x;
            x = amari;
        }
    }
}

int main() {
    ll n;
    cin >> n;
    ll m;
    if(n % 2 == 0){
        m = n / 2;
    }else{
        m = n;
    }

    ll ans = 0;
    

    srep(i,1,m+1){
        ll ii = i;
        if(ii * ii == m){
            ans += ii;
            break;
        }
        if(ii * ii > m)break;
        if(m % ii == 0){
            ans += ii + m / ii;
        }
    }
    
    cout << ans << endl;

    return 0;

}