use proconio::input;
use itertools::Itertools;

fn main() {
    input! {
        n: usize,
        ab: [(usize, usize); n],
    }
    let counts = ab.into_iter()
        .counts();
    if counts.values().any(|c| *c > 1) {
        println!("Yes");
    }
    else {
        println!("No");
    }
}