#include<bits/stdc++.h>
using namespace std;
#define FOR(i,s,t) for(int i = s; i < t; i++)
using LL = long long;
using VL = vector<LL>;

pair<VL, vector<bool>> make_prime(long long  N) {
	vector<long long >a;
	vector<bool> prime(N + 1);
	FOR(i, 0, N + 1) {
		prime[i] = 1;
	}prime[0] = prime[1] = 0;

	for (LL i = 2; i <= N; i++) {
		if (prime[i]) {
			a.push_back((long long)i);
			for (LL j = i * 2; j <= N; j += i)
				prime[j] = 0;
		}
	}
	return { a,prime };
}
int main() {
	int N; cin >> N;
	auto primes = make_prime(N);
	VL Ps = primes.first; // 41538	
	auto isprime = primes.second;
	LL ans = 0;
	FOR(i, 0, (int)Ps.size()) {
		LL r = Ps[i];
		if (r*r > 2 * N)break;
		FOR(j, 0, (int)Ps.size()) {
			LL p = Ps[j];
			LL q = r * r - p;
			if (0 <= q && q <= N) {
				ans += isprime[q];
			}
		}
	}
	cout << ans << endl;
}