#include using namespace std; //#define int long long #define all(v) (v).begin(), (v).end() #define rall(v) (v).rbegin(), (v).rend() #define rep(i,n) for(int i=0;i vi; typedef vector vc; typedef vector vb; typedef vector vd; typedef vector vs; typedef vector > vpii; typedef vector > vvi; typedef vector > vvc; typedef vector > vvb; typedef vector > vvd; typedef vector > vvs; typedef vector vl; typedef vector > vvl; typedef vector > > vvvl; ll MOD = 1000000007; const long long L_INF = 1LL << 60; const int INF = 2147483647; // 2^31-1 const double PI = acos(-1); //cout< inline bool chmin(T& a, T b) {if (a > b) {a = b;return true;}return false;} template inline bool chmax(T& a, T b) {if (a < b) {a = b;return true;}return false;} template void debug(T v){rep(i,v.size()) cout< P; signed main() { gearup; map mp; mp[{2,8}] = {2,8}; mp[{3,9}] = {3,9}; mp[{7,9}] = {7,9}; ll n;cin>>n; rep(i,n){ int x1,y1,x2,y2;cin>>x1>>y1>>x2>>y2; for(auto m:mp){ if(m.second == P(x1,y1)){ mp[m.first] = {x2,y2}; break; } } } if(mp[{2,8}] == P(5,8) && mp[{3,9}] == P(4,8) && mp[{7,9}] == P(6,8)) out("YES"); else out("NO"); }