use std::collections::HashSet;

use proconio::input;

fn main() {
    input! {
        n: usize,
        ab: [(i64, i64); n],
    }

    let mut set = HashSet::new();

    for i in 0..n {
        let (ai, bi) = ab[i];
        if set.contains(&(ai, bi)) {
            println!("Yes");
            return;
        }
        set.insert((ai, bi));
    }

    println!("No");
}