#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <unordered_map>
#include <chrono>
#include <random>
#include <bitset>
#include <iterator>
#include <functional>
#include <utility>
#include <cassert>
#pragma GCC optimize("O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma comment(linker, "STACK:36777216")
using namespace std;
using i64 = int64_t;
using i128 = __int128_t;
constexpr i64 MOD = 1e9 + 7;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
using vi = vector<i64>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using ii = pair<i64, i64>;

bool is_prime[303030];
int cnt[303030];
vi small_primes, primes;

void init() {
    for (int i = 2; i < 303030; i++) {
        is_prime[i] = 1;
    }
    for (int i = 2; i < 303030; i++) {
        if (is_prime[i] == false) continue;
        for (int j = 2; i * j < 303030; j++) {
            is_prime[i * j] = false;
        }
    }
    for (int i = 2; i < 303030; i++) {
        if (i < 100000 && is_prime[i]) small_primes.push_back(i);
        if (is_prime[i]) primes.push_back(i);
    }
}

int main() {
    init();
    int n;
    cin >> n;
    i64 ans = 0;
    for (int i = 1; i < primes.size(); i++) {
        int c = primes[i];
        if (c > n) break;
        int b = primes[i - 1];
        for (int j = 0; j < i - 1; j++) {
            cnt[primes[j] + b]++;
        }
        for (int j = 0; j < primes.size(); j++) {
            int sum = primes[j];
            if (sum - c >= 0) {
                ans += cnt[sum - c];
            }
        }
    }    cout << ans << endl;
}