import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        boolean[] isNotPrime = new boolean[n * 3];
        for (int i = 2; i <= Math.sqrt(n * 3); i++) {
            if (!isNotPrime[i]) {
                for (int j = 2; i * j < n * 3; j++) {
                    isNotPrime[i * j] = true;
                }
            }
        }
        ArrayList<Integer> primes = new ArrayList<>();
        for (int i = 3; i < n * 3; i++) {
            if (!isNotPrime[i]) {
                primes.add(i);
            }
        }
        int[] counts = new int[n * 3];
        counts[8]++;
        int max = 8;
        long ans = 0;
        for (int i = 2; primes.get(i) <= n; i++) {
            for (int j = i + 1; j < primes.size() && primes.get(j) - primes.get(i) <= max; j++) {
                ans += counts[primes.get(j) - primes.get(i)];
            }
            for (int j = 0; j < i; j++) {
                counts[primes.get(i) + primes.get(j)]++;
            }
            max = primes.get(i) + primes.get(i - 1);
        }
        System.out.println(ans);
    }
}