using System; using System.Collections.Generic; using System.Linq; using System.IO; //using System.Text; //using System.Text.RegularExpressions; //using System.Globalization; //using System.Diagnostics; using static System.Console; //using System.Numerics; //using static System.Math; //using pair = Pair; class Program { static void Main() { //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false }); new Program().solve(); Out.Flush(); } Scanner cin = new Scanner(); readonly int[] dd = { 0, 1, 0, -1, 0 }; //→↓←↑ readonly int mod = 1000000007; void chmax(ref T a, T b) where T : IComparable { a = a.CompareTo(b) < 0 ? b : a; } void chmin(ref T a, T b) where T : IComparable { a = a.CompareTo(b) < 0 ? a : b; } void solve() { int N = cin.nextint; eratos(3 * N); var cnt = new long[3 * N + 1]; long ans = 0; for (int i = 2; i < prime.Count; i++) { if (prime[i] > N) break; for (int j = 0; j < i - 1; j++) { cnt[prime[j] + prime[i - 1]]++; } foreach (var item in prime) { if(item - prime[i] >= 5) { ans += cnt[item - prime[i]]; } } } WriteLine(ans); } List prime; bool[] is_prime; void eratos(int n) { prime = new List(); is_prime = new bool[n + 1]; for (int i = 0; i <= n; i++) is_prime[i] = true; is_prime[0] = is_prime[1] = false; for (int i = 0; i <= n; i++) { if (is_prime[i]) { prime.Add(i); for (int j = 2 * i; j <= n; j += i) is_prime[j] = false; } } } int[] P; void phi(int n) { P = new int[n + 1]; for (int i = 0; i <= n; i++) P[i] = i; for (int i = 2; i <= n; i++) { if (is_prime[i]) { P[i] -= P[i] / i; for (int j = 2 * i; j <= n; j += i) P[j] -= P[j] / i; } } } } class Scanner { string[] s; int i; char[] cs = new char[] { ' ' }; public Scanner() { s = new string[0]; i = 0; } public string[] scan { get { return ReadLine().Split(); } } public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } } public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } } public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } } public string next { get { if (i < s.Length) return s[i++]; string st = ReadLine(); while (st == "") st = ReadLine(); s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries); i = 0; return next; } } public int nextint { get { return int.Parse(next); } } public long nextlong { get { return long.Parse(next); } } public double nextdouble { get { return double.Parse(next); } } }