28237
 13190
 39914
 81367
 8554
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 67448
 39004
 22308
 16054
 71468
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 300
 59632
 90783
 5611
 1000
 69475
 69753
 10
 5
 582
 8
 36961
 5071
 20
 53213
 92775
 28738
 100000
 92280
 37944
 9
 2627
 7
 3

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#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline T POW(T B, T P) {
  if (P == 0) return 1;
  if (P & 1)
    return B * POW(B, P - 1);
  else
    return (POW(B, P / 2)) * (POW(B, P / 2));
}
long long int Bigmod(long long int base, long long int power,
                     long long int mod) {
  if (power == 0) return 1 % mod;
  if (power == 1) return base % mod;
  long long int x = Bigmod(base, power / 2, mod);
  x = (x * x) % mod;
  if (power % 2) {
    x = (x * (base % mod)) % mod;
  }
  return x;
}
long long int Mulmod(long long int base, long long int power,
                     long long int mod) {
  if (power == 0) return 0;
  if (power == 1) return base % mod;
  long long int x = Mulmod(base, power / 2, mod);
  x = (x + x) % mod;
  if (power % 2) {
    x = (x + (base % mod)) % mod;
  }
  return x;
}
long long int BigMulmod(long long int base, long long int power,
                        long long int mod) {
  if (power == 0) return 1 % mod;
  if (power == 1) return base % mod;
  long long int x = BigMulmod(base, power / 2, mod);
  x = Mulmod(x, x, mod);
  if (power % 2) {
    x = Mulmod(x, (base % mod), mod);
  }
  return x;
}
bool isVowel(char ch) {
  ch = toupper(ch);
  if (ch == 'A' || ch == 'U' || ch == 'I' || ch == 'O' || ch == 'E')
    return true;
  return false;
}
long long int ModInverse(long long int number, long long int mod) {
  return Bigmod(number, mod - 2, mod);
}
bool isConso(char ch) {
  if (isalpha(ch) && !isVowel(ch)) return true;
  return false;
}
int toInt(string s) {
  int sm;
  stringstream second(s);
  second >> sm;
  return sm;
}
bool isPrime(long long int val) {
  if (val == 2) return true;
  if (val % 2 == 0 || val == 1) return false;
  long long int sqrt_N = (long long int)((double)sqrt(val));
  for (long long int i = 3; i <= sqrt_N; i += 2) {
    if (val % i == 0) return false;
  }
  return true;
}
template <class T>
string convert(T _input) {
  stringstream blah;
  blah << _input;
  return blah.str();
}
vector<int> graph[200005], cost[200005];
int visited[10005];
void make_graph(int u, int v, int x) {
  graph[u].push_back(v);
  cost[u].push_back(x);
  graph[v].push_back(u);
  cost[v].push_back(x);
}
int sum;
void DFS(int u) {
  if (visited[u] == 1) return;
  visited[u] = 1;
  for (int i = 0; i < graph[u].size(); i++) {
    sum += cost[u][i];
    DFS(graph[u][i]);
  }
}
int main() {
  int n;
  scanf("%d", &(n));
  for (int i = 2; i <= n; i++) {
    for (int j = i * 2; j <= n; j += i) {
      make_graph(i + n, j + n, (int)(j / i));
      make_graph(i, j + n, (int)(j / i));
      make_graph(i + n, j, (int)(j / i));
      make_graph(i, j, (int)(j / i));
    }
  }
  for (int i = 0; i <= 2 * n; i++) {
    for (int j = 0; j < (int)cost[i].size(); j++) sum += cost[i][j];
  }
  cout << sum / 2 << endl;
  return 0;
}
