use proconio::input;

fn main() {
	input! {
		n: usize,
		m: usize,
		pq: [(usize, usize); m],
	}

    let mut pos = n;

    for (p, q) in pq {
        if pos == p {
            pos = q;
        } else if pos == q {
            pos = p;
        }
    }

    println!("{pos}");
}