#include <bits/stdc++.h>
using namespace std;
const long long int MOD = 1000000007;
const long double PI = 3.14159265;
long long int powerWithMod(long long int base, long long int exponent,
                           long long int modulus = LLONG_MAX) {
  long long int result = 1;
  base %= modulus;
  while (exponent > 0) {
    if (exponent % 2 == 1) result = (result * base) % modulus;
    exponent >>= 1;
    base = (base * base) % modulus;
  }
  return result;
}
long long int modInverse(long long int a, long long int m = MOD) {
  return powerWithMod(a, m - 2, m);
}
int gets(int a) {
  int lim = (int)sqrt(a) + 1;
  for (int i = 2; i < lim; i++) {
    if (a % i == 0) return a / i;
  }
  return 1;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int n;
  cin >> n;
  long long int ans = n;
  while (n > 1) {
    n = gets(n);
    ans += n;
  }
  cout << ans << "\n";
  return 0;
}
