#[allow(unused_imports)]
use std::cmp::*;
#[allow(unused_imports)]
use std::collections::*;
#[allow(unused_imports)]
use std::io::{Write, BufWriter};
// https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    ($($r:tt)*) => {
        let stdin = std::io::stdin();
        let mut bytes = std::io::Read::bytes(std::io::BufReader::new(stdin.lock()));
        let mut next = move || -> String{
            bytes.by_ref().map(|r|r.unwrap() as char)
                .skip_while(|c|c.is_whitespace())
                .take_while(|c|!c.is_whitespace())
                .collect()
        };
        input_inner!{next, $($r)*}
    };
}

macro_rules! input_inner {
    ($next:expr) => {};
    ($next:expr,) => {};
    ($next:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($next, $t);
        input_inner!{$next $($r)*}
    };
}

macro_rules! read_value {
    ($next:expr, ( $($t:tt),* )) => { ($(read_value!($next, $t)),*) };
    ($next:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
    };
    ($next:expr, chars) => {
        read_value!($next, String).chars().collect::<Vec<char>>()
    };
    ($next:expr, usize1) => (read_value!($next, usize) - 1);
    ($next:expr, [ $t:tt ]) => {{
        let len = read_value!($next, usize);
        read_value!($next, [$t; len])
    }};
    ($next:expr, $t:ty) => ($next().parse::<$t>().expect("Parse error"));
}

#[allow(unused)]
trait Change { fn chmax(&mut self, x: Self); fn chmin(&mut self, x: Self); }
impl<T: PartialOrd> Change for T {
    fn chmax(&mut self, x: T) { if *self < x { *self = x; } }
    fn chmin(&mut self, x: T) { if *self > x { *self = x; } }
}

fn main() {
    // In order to avoid potential stack overflow, spawn a new thread.
    let stack_size = 104_857_600; // 100 MB
    let thd = std::thread::Builder::new().stack_size(stack_size);
    thd.spawn(|| solve()).unwrap().join().unwrap();
}

fn dfs(v: usize, g: &[Vec<(usize, bool)>], vis: &mut [bool], pot: &mut [bool], p: bool) -> Option<()>{
    if vis[v] {
        if pot[v] != p {
            return None;
        }
        return Some(());
    }
    vis[v] = true;
    pot[v] = p;
    for &(u, sw) in &g[v] {
        dfs(u, g, vis, pot, p ^ sw)?;
    }
    Some(())
}

fn solve() {
    input! {
        m: usize,
        abc: [[i32; 3]; m],
    }
    let mut seen = HashMap::new();
    for i in 0..m {
        for j in 0..3 {
            let x = abc[i][j];
            let y = abc[i][(j + 1) % 3];
            let (x, y, sw) = if x < y {
                (x, y, false)
            } else {
                (y, x, true)
            };
            seen.entry((x, y)).or_insert(vec![]).push((i, sw));
            if seen[&(x, y)].len() >= 3 {
                println!("NO");
                return;
            }
        }
    }
    let mut g = vec![vec![]; m];
    for (_, v) in seen {
        if v.len() != 2 {
            continue;
        }
        let (a, sw0) = v[0];
        let (c, sw1) = v[1];
        g[a].push((c, sw0 == sw1));
        g[c].push((a, sw0 == sw1));
    }
    let mut vis = vec![false; m];
    let mut pot = vec![false; m];
    for i in 0..m {
        if !vis[i] {
            if dfs(i, &g, &mut vis, &mut pot, false).is_none() {
                println!("NO");
                return;
            }
        }
    }
    println!("YES");
}