#include<bits/stdc++.h>
#include <atcoder/all>
#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace atcoder;
using mint=modint998244353;
using namespace std;
using ll=long long;
using ul=unsigned long long;
int dx[9] = {-1, 1, 0, 0, -1, -1, 1, 1, 0};
int dy[9] = {0, 0, -1, 1, -1, 1, -1, 1, 0};
using Graph=vector<vector<int>>;
ll op(ll a,ll b){return min(a,b);}
ll e(){return 2e9;}
vector<ll> erat(int Max){
	vector<ll>ans;
	vector<bool>check(Max+1);
	for(int i=2;i<=Max;i++){
		if(check[i])continue;
		else{
			ans.push_back(i);
			for(int j=i*2;j<=Max;j+=i)check[j]=1;
		}
	}
	return ans;
}
int main(){
	int N;
	cin>>N;
	int cnt=0;
	vector<ll>A=erat(N);
	for(int i=0;i<A.size();i++){
		for(int j=0;A[j]*A[j]<=N;j++){
			if(binary_search(A.begin(),A.end(),A[j]*A[j]-A[i]))cnt++;
		}
	}
	cout<<cnt<<endl;
}