#include <iostream>
#include <vector>
using namespace std;

struct SieveEratos{
  vector<bool> t;
  SieveEratos(int n):t(n+1,true){
    t[0] = t[1] = false;
    for(int i = 2; n >= i; i++){
      if(t[i]){
        for(int j = i+i; n >= j; j+=i){
          t[j] = false;
        }
      }
    }
  }
  bool operator[](int x){return t[x];}
};



int main(){
  int n;cin>>n;
  SieveEratos A(n);
  int ans = 0;
  for(int i = 0; n >= i*i; i++){
    if(!A[i])continue;
    for(int j = 0; (i*i)/2 >= j; j++){
      if(A[j] && A[(i*i)-j]){
          ans++;
          if(j+j != i*i)ans++;
      }
    }
  }
  cout << ans << endl;
}