#include <bitset>
#include <iostream>

int main() {
  int n;
  std::cin >> n;
  std::bitset<50000001> used;
  long ans = 0;
  for (int i = 1; i <= n; ++i) {
    if (used[i]) continue;
    long size = 0;
    for (long j = 1; j * j * i < n; ++j) {
      used[j * j * i] = 1;
      ++size;
    }
    ans += size * size;
  }
  std::cout << ans << "\n";
}