#include <algorithm>
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(), (x).end()
#define ll long long
#define ld long double
#define INF 1000000000000000000
typedef pair<ll, ll> pll;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;
    int MAX = N + 1;
    vector<int> is_prime(MAX, 1);
    vector<ll> primes, pows;
    is_prime[0] = 0, is_prime[1] = 0;
    for (int i = 2; i < MAX; ++i) {
        if (!is_prime[i])
            continue;
        for (int j = 2 * i; j < MAX; j += i)
            is_prime[j] = 0;
    }

    rep(i, MAX) {
        if (is_prime[i]) {
            primes.push_back(i);
            if ((ll)i * i <= N * 2)
                pows.push_back(i * i);
        }
    }

    int cnt = 0;
    rep(i, primes.size()) {
        rep(j, pows.size()) {
            if (primes[i] > pows[j] || pows[j] - primes[i] > N)
                continue;
            else if (is_prime[pows[j] - primes[i]])
                cnt++;
        }
    }

    cout << cnt << endl;
}