// includes #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include // macros #define ll long long int #define pb emplace_back #define mk make_pair #define pq priority_queue #define FOR(i, a, b) for(int i=(a);i<(b);++i) #define rep(i, n) FOR(i, 0, n) #define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--) #define all(x) (x).begin(),(x).end() #define sz(x) ((int)(x).size()) #define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) using namespace std; // types typedef pair P; typedef pair Pl; typedef pair Pll; typedef pair Pd; // constants const int inf = 1e9; const ll linf = 1LL << 50; const double EPS = 1e-10; const int mod = 1e9 + 7; // solve template bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;} template bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;} template vector list_prime(T n){ vector res; vector i_prime = vector(n+1, true); for(ll i = 2; i <= n; i++){ if(i_prime[i]){ res.push_back(i); for(ll j = 2; j * i <= n; j++){ i_prime[i * j] = false; } } } return res; } template T power(T a, T n, T mod) { T res = 1; T tmp = n; T curr = a; while(tmp){ if(tmp % 2 == 1){ res = (T)((ll)res * curr % mod); } curr = (T)((ll)curr * curr % mod); tmp >>= 1; } return res; } template bool suspect(T a, int s, T d, T n){ T x = power(a, d, n); if(x == 1)return true; for(int r = 0; r < s; r++){ if(x == n - 1)return true; x = x * x % n; } return false; } template bool millar_rabin(T n){ if(n <= 1 || (n > 2 && n % 2 == 0))return false; vector test = {2, 3, 5, 7, 11, 13, 17, 19, 23}; T d = n - 1; int s = 0; while(d % 2 == 0)s++, d /= 2; for(int i = 0; i < test.size() && test[i] < n; i++){ if(!suspect(test[i], s, d, n))return false; } return true; } ll cnt[300001]; int main(int argc, char const* argv[]) { ios_base::sync_with_stdio(false); cin.tie(0); int n; cin >> n; auto p = list_prime(3 * n); ll res = 0; for(int i = 0; p[i] <= n; i++){ for(int j = i + 1; j < sz(p); j++){ int tmp = p[j] - p[i]; res += cnt[tmp]; } for(int j = 0; j < i; j++){ cnt[p[i] + p[j]]++; } } cout << res << endl; return 0; }