#include using namespace std; typedef long long ll; typedef long double ld; #define REP(i, n) for (int i = 0; i < (n); ++i) #define REPR(i, n) for (int i = n - 1; i >= 0; --i) #define FOR(i, m, n) for (int i = m; i < n; ++i) #define FORR(i, m, n) for (int i = m; i >= n; --i) #define ALL(v) (v).begin(),(v).end() #define ALLR(v) (v).rbegin(),(v).rend() #define fi first #define se second #define PB push_back #define EB emplace_back using P = pair; template using PQ = priority_queue; template using QP = priority_queue,greater>; templatevoid debug(const T &v,ll h,ll w){for(ll i=0;ivoid debug(const T &v,ll n){for(ll i=0;ivoid debug(const vector&v){debug(v,v.size());} templatevoid debug(const vector>&v){for(auto &vv:v)debug(vv,vv.size());} templatevoid debug(stack st){while(!st.empty()){cout<void debug(queue st){while(!st.empty()){cout<void debug(deque st){while(!st.empty()){cout<void debug(PQ st){while(!st.empty()){cout<void debug(QP st){while(!st.empty()){cout<void debug(const set&v){for(auto z:v)cout<void debug(const multiset&v){for(auto z:v)cout<void debug(const array &a){for(auto z:a)cout<void debug(const map&v){for(auto z:v)cout<<"["<bool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b> n; vector p(3*n+1,true); p[0]=p[1]=false; for(int i=2;i*i<=3*n;i++){ if(p[i]) for(int j=2;j*i<=3*n;j++) p[i*j]=false; } vector sm(3*n+1); vector pl; REP(i,n+1) if(p[i]) pl.PB(i); for(auto x:pl){ for(auto y:pl) if(x pabc; REP(i,3*n+1) if(p[i]) pabc.PB(i); ll pmx=5; vector c(3*n+1); c[5]++; FOR(i,2,pl.size()){ REP(j,pabc.size()){ if(pl[i]>pabc[j]) continue; if(pabc[j]-pl[i]>pmx) continue; ans+=c[pabc[j]-pl[i]]; } REP(j,i) c[pl[i]+pl[j]]++; chmax(pmx,pl[i]+pl[i-1]); } cout << ans << endl; }