#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> F(N + 1);
  for (int i = 1; i <= N; i++){
    F[i] = i;
  }
  for (int i = 2; i * i <= N; i++){
    if (F[i * i] == i * i){
      for (int j = i * i; j <= N; j += i * i){
        while (F[j] % (i * i) == 0){
          F[j] /= i * i;
        }
      }
    }
  }
  vector<int> cnt(N + 1, 0);
  for (int i = 1; i <= N; i++){
    cnt[F[i]]++;
  }
  long long ans = 0;
  for (int i = 1; i <= N; i++){
    ans += cnt[i] * cnt[i];
  }
  cout << ans << endl;
}