#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int64_t N;
  cin >> N;
  vector<bool> is_prime(3 * N + 1, true);
  is_prime[0] = is_prime[1] = false;
  for (int64_t i = 0; i * i < 3 * N + 1; i++) {
    if (!is_prime[i]) continue;
    for (int k = 2 * i; k < 3 * N + 1; k += i) {
      is_prime[k] = false;
    }
  }
  vector<int64_t> primes;
  for (int64_t i = 0; i < N + 1; i++) {
    if (is_prime[i]) {
      primes.emplace_back(i);
    }
  }
  int res = 0;
  for (auto r : primes) {
    if (r * r - 2 * primes.back() > 0) break;
    for (auto p : primes) {
      auto q = r * r - p;
      if (q < N + 1 && q > 0 && is_prime[q]) res++;
    }
  }
  cout << res << '\n';
  return 0;
}