#include <bits/stdc++.h>
using namespace std;
#define overload3(_NULL, _1, _2, name, ...) name
#define rep1(i, n) for (remove_const_t<remove_reference_t<decltype(n)>> i = 0; i < (n); i++)
#define rep2(i, a, b) for (remove_const_t<remove_reference_t<decltype(b)>> i = (a); i < (b); i++)
#define rep(...) overload3(__VA_ARGS__, rep2, rep1)(__VA_ARGS__)
#if __has_include(<debug.hpp>)
#    include <debug.hpp>
#else
#    define dbg(...) (void(0))
#endif
template<class T> void drop(const T &x) {
    cout << x << "\n";
    exit(0);
}
template<class T, class U = T> bool chmin(T &a, U &&b) { return b < a ? a = forward<U>(b), true : false; }
template<class T, class U = T> bool chmax(T &a, U &&b) { return a < b ? a = forward<U>(b), true : false; }
using i64 = long long;
using usize = size_t;

int main() {
    int n;
    cin >> n;
    i64 ans = 0;
    for (int i = 2; i * i <= n; i++) {
        while (n % i == 0) {
            n /= i;
            ans += i;
        }
    }
    if (n > 1) ans += n;
    cout << ans << endl;
}

__attribute__((constructor)) static void io_setup() noexcept {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
}