use proconio::input;
use std::collections::HashMap;
fn main() {
    input! {
        n: usize,
        ab: [(usize, usize); n],
    }
    let mut counts = HashMap::new();
    for ab in ab {
        *counts.entry(ab).or_insert(0) += 1;
    }
    if counts.values().any(|c| *c > 1) {
        println!("Yes");
    }
    else {
        println!("No");
    }
}