#include <iostream>
#include <vector>

using namespace std;

int main() {

int S;
cin >> S;

vector<int> sum_div(S + 1, 0);
for (int i = 1; i <= S; ++i) {
    for (int j = 1; j < i; ++j) {
        if (i % j == 0) {
            sum_div[i] += j;
        }
    }
}

vector<int> dp(S + 1, 0);
for (int i = 1; i <= S; ++i) {
    for (int j = S; j >= i; --j) {
        dp[j] = max(dp[j], dp[j - i] + sum_div[i]);
    }
}

int max_sum = 0;
for (int j = 0; j <= S; ++j) {
    if (dp[j] > max_sum) {
        max_sum = dp[j];
    }
}

cout << max_sum << endl;
return 0;

}