#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
  #define _GLIBCXX_DEBUG
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  int n;
  cin >> n;
  int 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;
  return 0;
}