#include using namespace std; #define int long long #define rep(i,n) for(int i=0;i<(n);i++) #define pb push_back #define all(v) (v).begin(),(v).end() #define fi first #define se second typedef vectorvint; typedef pairpint; typedef vectorvpint; templateinline void chmin(A &a,B b){if(a>b)a=b;} templateinline void chmax(A &a,B b){if(auku(){ vint ret(3); rep(i,3)cin>>ret[i]; return ret; } int cross(vint A,vint B,vint C){ int ret=0; rep(i,3)ret+=(B[i]-A[i])*(C[i]-A[i]); return ret; } signed main(){ vint A,B,C,D; A=uku();B=uku();C=uku();D=uku(); vint latte; latte.pb(cross(A,B,D)); latte.pb(cross(B,C,D)); latte.pb(cross(C,D,A)); sort(all(latte)); if(latte[0]>0||latte[2]<0)cout<<"YES"<