#include using namespace std; #include using namespace atcoder; //using mint = static_modint<998244353>; using mint = static_modint<1000000007>; ostream &operator<<(ostream &o,const mint &m){cout<; using vl = vector; template using ve = vector; template using vv = vector>; template using vvv = vector>; #define rep(i,n) for(ll i=0;i<(ll)(n);++i) #define reps(i,s,n) for(ll i=(s);i<(ll)(n);++i) #define rep1(i,n) for(ll i=1;i<=(ll)(n);++i) #define fi first #define se second #define pb push_back #define eb emplace_back #define be(v) (v).begin(),(v).end() const long long INF = 1e18; #ifdef DEBUG #include random_device rd; mt19937 gen(rd()); ll random(ll l,ll h){ uniform_int_distribution dist(l,h); return dist(gen); } #endif vector prime_number(const long long N) { vector is_prime(N+1,true); vector P; for(ll i = 2; i <= N; i++ ) { if( is_prime[ i ] ) { for( ll j = 2 * i; j <= N; j += i ) { is_prime[ j ] = false; } P.emplace_back( i ); } } return P; } ll N; void input(){ cin>>N; } #ifdef DEBUG void showall(){ show(N); } #endif ll logic(){ ll ans=0; vl p = prime_number(3*N); vl cnt(3*N+1,0); for(ll i = 2; p.at(i) <= N; ++i){ rep(j,i-1){ cnt.at(p.at(j)+p.at(i-1))++; } reps(j,i+1,p.size()){ ans += cnt.at(p.at(j) - p.at(i)); } } return ans; } #ifdef DEBUG ll naive(){ return 1; } #endif int main(){ input(); #ifdef DEBUG showall(); cout << "--- Logic ---" << endl; #endif ll ans=logic(); cout<