use std::collections::*;

type Map<K, V> = BTreeMap<K, V>;

fn main() {
    input! {
        a: [String; 6],
    }
    let mut index = Map::new();
    for a in a.iter() {
        if !index.contains_key(a) {
            let k = index.len();
            index.insert(a.clone(), k);
        }
    }
    let nand = |a: bool, b: bool| -> bool { !(a && b) };
    let ans = (0..(1 << index.len())).any(|bit| {
        let get = |x: usize| -> bool {
            let k = index[&a[x]];
            bit >> k & 1 == 1
        };
        nand(
            nand(nand(get(0), get(1)), get(2)),
            nand(nand(get(3), get(4)), get(5)),
        )
    });
    if ans {
        println!("YES");
    } else {
        println!("NO");
    }
}

// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[macro_export]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[macro_export]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[macro_export]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------