package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	m:=map[string]string{}
	for ;n>0;n-- {
		var x1,y1,x2,y2 string
		Scan(&x1,&y1,&x2,&y2)
		k1:=x1+","+y1
		k2:=x2+","+y2
		e:=m[k1]
		if e=="" {
			e=k1
		}
		m[k1]=""
		m[k2]=e
	}
	r:=m["5,8"]=="2,8"&&
	 m["4,8"]=="3,9"&&
	 m["6,8"]=="7,9"
	if r {
		Println("YES")
	} else {
		Println("NO")
	}
}