use std::io::{self, Stdin};
use std::str::{self, FromStr};
use std::error::Error;
use std::thread;
use std::collections::*;

fn exec() {
    let mut sc = Scanner::new();
    let n: usize = sc.ne();
    let mut edge = vec![(0, 0); n];
    let mut num = BTreeMap::new();
    for i in 0..n {
        let y1: usize = sc.ne::<usize>() - 1;
        let x1: usize = sc.ne::<usize>() - 1;
        let y2: usize = sc.ne::<usize>() - 1;
        let x2: usize = sc.ne::<usize>() - 1;
        let n1 = y1 * 100 + x1;
        let n2 = y2 * 100 + x2;
        edge[i] = (n1, n2);
        num.insert(n1, 0);
        num.insert(n2, 0);
    }
    let mut t = 0;
    for (_, val) in num.iter_mut() {
        *val = t;
        t += 1;
    }
    let m = num.len();
    let mut adj = vec![Vec::new(); m];
    for &(u_, v_) in &edge {
        let u = num[&u_];
        let v = num[&v_];
        adj[u].push(v);
        adj[v].push(u);
    }
    fn dfs(mut used: &mut Vec<bool>, adj: &Vec<Vec<usize>>, cur: usize, par: usize) -> i32 {
        used[cur] = true;
        let mut res = 0;
        for &nxt in &adj[cur] {
            if nxt == par {
                continue;
            }
            if used[nxt] {
                res += 1;
            } else {
                res += dfs(&mut used, &adj, nxt, cur);
            }
        }
        res
    }
    let mut used = vec![false; m];
    let mut ok = true;
    for i in 0..m {
        if used[i] {
            continue;
        }
        ok &= dfs(&mut used, &adj, i, i) < 4;
    }
    println!("{}", if ok { "YES" } else { "NO" });
}

const DEFAULT_STACK: usize = 16 * 1024 * 1024;
fn main() {
    let builder = thread::Builder::new();
    let th = builder.stack_size(DEFAULT_STACK);
    let handle = th.spawn(|| { exec(); }).unwrap();
    let _ = handle.join();
}

#[allow(dead_code)]
struct Scanner {
    stdin: Stdin,
    id: usize,
    buf: Vec<u8>,
}

#[allow(dead_code)]
impl Scanner {
    fn new() -> Scanner {
        Scanner {
            stdin: io::stdin(),
            id: 0,
            buf: Vec::new(),
        }
    }
    fn next_line(&mut self) -> Option<String> {
        let mut res = String::new();
        match self.stdin.read_line(&mut res) {
            Ok(0) => return None,
            Ok(_) => Some(res),
            Err(why) => panic!("error in read_line: {}", why.description()),
        }
    }
    fn next<T: FromStr>(&mut self) -> Option<T> {
        while self.buf.len() == 0 {
            self.buf = match self.next_line() {
                Some(r) => {
                    self.id = 0;
                    r.trim().as_bytes().to_owned()
                }
                None => return None,
            };
        }
        let l = self.id;
        assert!(self.buf[l] != b' ');
        let n = self.buf.len();
        let mut r = l;
        while r < n && self.buf[r] != b' ' {
            r += 1;
        }
        let res = match str::from_utf8(&self.buf[l..r]).ok().unwrap().parse::<T>() {
            Ok(s) => Some(s),
            Err(_) => panic!("parse error"),
        };
        while r < n && self.buf[r] == b' ' {
            r += 1;
        }
        if r == n {
            self.buf.clear();
        } else {
            self.id = r;
        }
        res
    }
    fn ne<T: FromStr>(&mut self) -> T {
        self.next::<T>().unwrap()
    }
}