#include <algorithm>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)
using namespace std;
typedef long long int lli;
/*
 * 係数がわかれば良い
 * sum suc(n) = (nx+n(n+1)/2)
 */
lli gcd(lli A, lli B)
{
    if (B > A)
        swap(A, B);
    if (A % B == 0)
        return B;
    else
        return gcd(B, A % B);
}
lli sum_of_yakusuu(lli N)
{
    lli ans = 0;
    lli cnt = 1;
    while (cnt * cnt <= N) {
        if (N % cnt == 0)
            ans += cnt + N / cnt;
        if (N == cnt * cnt) {
            ans -= cnt;
        }
        cnt++;
    }
    return ans;
}

int main()
{
    lli n;
    cin >> n;
    if (n & 1) {
        cout << sum_of_yakusuu(n) << endl;
    } else {
        cout << sum_of_yakusuu(n / 2 * gcd(2, (n + 1))) << endl;
    }
}