#include <bits/stdc++.h>
using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL,LL> PLL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef vector<bool> VB;
typedef vector<VB> VVB;
typedef vector<double> VD;
typedef vector<VD> VVD;
typedef vector<string> VS;
typedef vector<VS> VVS;
typedef vector<char> VC;
typedef vector<VC> VVC;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
typedef priority_queue<int> PQGI; //大きい順
typedef priority_queue<int, VI, greater<int>> PQLI;
typedef priority_queue<PII> PQGP;
typedef priority_queue<PII, VPII, greater<PII>> PQLP;
//priority_queue<T,vector<T>,decltype(f)> pq{f};

//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EB emplace_back
#define EF emplace_front
#define PB push_back
#define PF push_front
#define POB pop_back
#define POF pop_front
#define MP make_pair
#define SZ(a) (int)((a).size())
#define SQ(a) ((a)*(a))
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define SORTR(c) sort((c).rbegin(), (c).rend())
#define LB lower_bound
#define UB upper_bound
#define NEXP(a) next_permutation((a).begin(),(a).end())
#define FI first
#define SE second
#define Vmin(a) *min_element((a).begin(),(a).end())
#define Vmax(a) *max_element((a).begin(),(a).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define FORR(i,a,b) for(int i = (b-1);i>=(a);i--)
#define REPR(i,n) FORR(i,0,n)
#define CFOR(i,a,b) for(int i=(a);i<=(b);++i)
#define CREP(i,n)  CFOR(i,0,n)
#define CFORR(i,a,b) for(int i = (b);i>=(a);i--)
#define CREPR(i,n) CFORR(i,0,n)
#define BFOR(bit,a,b) for(int bit = (a); bit < (1ll<<(b)); ++bit)
#define BREP(bit,n) BFOR(bit,0,n)

//constant
//--------------------------------------------
const double EPS = 1e-10;
const double PI  = acos(-1.0);
const int INF = INT_MAX/2;
const LL LINF = LLONG_MAX/3;
const int RINF = INT_MIN/2;
const LL RLINF = LLONG_MIN/3;
const LL MOD = 1e9+7;
const LL MODD = 998244353;
const int MAX = 510000;

inline bool Eq(double a, double b) { return fabs(b - a) < EPS; }

//other
//-------------------------------------------
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define ISIN(x,l,r) ((l) <= (x) && (x) < (r))
#define CEIL(x,y) (((x)+(y)-1)/(y))
inline LL toLL(string s) {LL v; istringstream sin(s);sin>>v;return v;}

template<typename T>
T Vsum(vector<T> &v){T res(0);for(auto&&x:v) res += x; return res; }
template<typename T>
T Vgcd(vector<T> &v){T res(0);for(auto&&x:v) res=gcd(res,x); return res; }
template<typename T>
T Vlcm(vector<T> &v){T res(1);for(auto&&x:v) res=lcm(res,x); return res; }

#define COUT(x) cout << (x) << endl
#define COUT2(x,y) cout << (x) << " " << (y) << endl
#define COUT3(x,y,z) cout << (x) << " " << (y) << " " << (z) << endl
#define BC(x) __builtin_popcountll(x)

VI dx = {1,0,-1,0,1,1,-1,-1};
VI dy = {0,1,0,-1,1,-1,1,-1};

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}
template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 >& p) {
  os << p.first << " " << p.second;
  return os;
}
template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}
template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < SZ(v); i++) {
    os << v[i] << (i + 1 != SZ(v) ? " " : "");
  }
  return os;
}

template<typename T>
vector<T> make_v(size_t a,T b){return vector<T>(a,b);}
template<typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v(ts...))>(a,make_v(ts...));
}

struct FastFactor{
  int n;
  VI min_factor;

  FastFactor(int _n):n(_n+1),min_factor(_n+1){
    iota(ALL(min_factor),0);
    for(int i = 2; i*i < n; ++i){
      if(min_factor.at(i) < i) continue;
      for(int j = i*i; j < n; j += i){
        if(min_factor.at(j) == j) min_factor.at(j) = i;
      }
    }
  }

  map<int,int> factor(int a){
    map<int,int> res;
    while(a > 1){
      res[min_factor.at(a)]++;
      a /= min_factor.at(a);
    }
    return res;
  }

  bool isPrime(int p){
    if(p<=1) return false;
    if(p>=n) return false;
    return p == min_factor.at(p);
  }

  VI prime_table(){
    VI res;
    REP(i,n){
      if(isPrime(i)) res.PB(i);
    }
    return res;
  }
};

int main() {

  // cin.tie(0);
  // ios::sync_with_stdio(false);
  cout << fixed << setprecision(12);
  
  int N;
  cin >> N;
  if(N == 1){
    COUT(0);
    return 0;
  }

  FastFactor ff(N);
  VI pt = ff.prime_table();
  int ans = 0;
  for(auto p : pt){
    if(p==2)continue;
    LL q = (LL)p*p-2;
    if(q>N){
      //if(ff.isPrime(q))COUT(q);
      continue;
    }
    if(ff.isPrime(q)) ans++;
  }
  ans *= 2; ans++;

  COUT(ans);

  return 0;
}