use proconio::input;
use ac_library::Dsu;

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

    let mut uf = Dsu::new(2*n);
    for (u, v) in &e{
        uf.merge(u-1, n+v-1);
        uf.merge(v-1, n+u-1);
    }

    let mut ok = true;
    for (u, v) in &e{
        if uf.same(u-1, v-1){
            ok = false;
        }
    }

    println!("{}", if ok{"Yes"} else{"No"});
}