#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,m,n) for(int i=m; i<n; ++i)
#define repl(i,m,n) for(ll i=m; i<n; ++i)

int main(){
    int N;
    cin >> N;

    vector<bool> is_prime(500010, true);
    vector<int> prime_list;

    is_prime[0] = is_prime[1] = false;
    for(int i=2; i<=500010; ++i){
        if(!is_prime[i]) continue;
        prime_list.push_back(i);
        for(int j=2*i; j<=500010; j+=i){
            is_prime[j] = false;
        }
    }

    int ans = 0;
    for(int r : prime_list){
        if(r*r >= 2*N || r > N) break;
        for(int p : prime_list){
            if(r*r <= p || p > N) break;
            int q = r*r - p;
            if(is_prime[q] && q <= N) ans++;
        }
    }
    cout << ans << endl;

    return 0;
}