#include <bits/stdc++.h>
#define rep(i, n) for(long long i = 0; i < (long long)(n); i++)
using namespace std;
using ll = long long;


class eratosthenes {
public:
	vector<int> prime_n;
	bool prime[500001];

	eratosthenes() {
		fill(prime, prime + 500001, true); //素数
		prime[0] = prime[1] = false;
		for (int i = 2; i < 500001; i++) {
			if (prime[i] == true) {
				prime_n.push_back(i);
				for (int j = 2; i * j < 500001; j++) {
					prime[i * j] = false;
				}
			}
		}
	}
};

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

    eratosthenes p;

    vector<int> prime;
    rep(i, p.prime_n.size()){
        if(p.prime_n[i] > n) break;
        prime.push_back(p.prime_n[i]);
    }

    vector<int> sprime;
    rep(i, prime.size()){
        if(prime[i] * prime[i] > n*n) break;
        sprime.push_back(prime[i] * prime[i]);
    }

    set<int> st;
    rep(i, prime.size()){
        if(prime[i] > n) break;
        st.insert(prime[i]);
    } 


    int ans = 0;
    rep(i, prime.size()){
        rep(j, sprime.size()){
            int tmp = sprime[j] - prime[i];
            if(tmp < 0) continue;
            if(tmp <= n && st.find(tmp) != st.end()) ans++;
        }
    }

    cout << ans << endl;

    return 0;
}