#include <bits/stdc++.h>

namespace DECLARATIONS {
  using namespace std;

  using ll = long long;
  using PI = pair<int, int>;
  template<class T> using V = vector<T>;
  using VI = V<int>;
#define _1 first
#define _2 second

#ifdef MY_DEBUG
# define DEBUG(x) x
#else
# define DEBUG(x)
#endif

  template<class T>
  inline void debug(T &A) {
    DEBUG(
        for (const auto &a : A) {
          cerr << a << " ";
        }
        cerr << '\n';
    )
  }

  template<class T>
  inline void debug_dim2(T &A) {
    DEBUG(
        for (const auto &as : A) {
          debug(as);
        }
    )
  }

  template<typename ... Args>
  inline void debug(const char *format, Args const &... args) {
    DEBUG(
        fprintf(stderr, format, args ...);
        cerr << '\n';
    )
  }

  template<typename ... Args>
  string format(const std::string &fmt, Args ... args) {
    size_t len = std::snprintf(nullptr, 0, fmt.c_str(), args ...);
    std::vector<char> buf(len + 1);
    std::snprintf(&buf[0], len + 1, fmt.c_str(), args ...);
    return std::string(&buf[0], &buf[0] + len);
  }
}
using namespace DECLARATIONS;

const int MOD = 1000000007;

class PrimeFactorization {
public:
  VI prime, factor;

  PrimeFactorization(int MAX): factor(MAX + 1) {
    for (int i = 2; i <= MAX; ++i) {
      if (factor[i] == 0) {
        factor[i] = i;
        prime.push_back(i);
      }

      int p = 0;
      while (p < prime.size() && prime[p] * i <= MAX) {
        factor[prime[p] * i] = prime[p];
        if (prime[p] == i) break;
        p++;
      }
    }
  }
};

int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int N;
  cin >> N;

  int ans = 0;
  PrimeFactorization pf(N);
  V<bool> rev(N + 1);
  for (int p : pf.prime) {
    rev[p] = true;
  }
  for (int i = 0; i < pf.prime.size() && pf.prime[i] * pf.prime[i] <= 2 * N; ++i) {
    int r = pf.prime[i];
    for (int p : pf.prime) {
      int q = r * r - p;
//      debug("p:%d q:%d r:%d", p, q, r);
      if (q > 1 && q <= N && rev[q]) ans++;
    }
  }
  cout << ans;
}