#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define int long long
using namespace std;
typedef pair<int, int> P;
const int mod = 1000000007;
const int INF = 1e18;

const int MAX_N = 500010;
int prime[MAX_N];
bool is_prime[MAX_N + 1];
int sieve(int n){
    int p = 0;
    for(int i = 0; i <= n; i++) is_prime[i] = true;
    is_prime[0] = is_prime[1] = false;
    for(int i = 2; i <= n; i++){
        if(is_prime[i]){
            prime[p++] = i;
            for(int j = 2*i; j <= n; j += i) is_prime[j] = false;
        }
    }
    return p;
}

signed main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    int p = sieve(n + 1);
    int ans = 0;
    rep(i, 0, p){
        int tmp = prime[i] * prime[i];
        if(tmp > 1000000) break;
        rep(j, 0, p){
            int tmp2 = tmp - prime[j];
            if(tmp2 <= 0) break;
            if(tmp2 > n) continue;
            if(is_prime[tmp2]) ans++;
        }
    }
    cout << ans << endl;
}