use std::io::Write;

fn main() {
    let ref mut buf = Vec::new();
    std::io::Read::read_to_end(&mut std::io::stdin(), buf).ok();
    let mut iter = std::str::from_utf8(buf).unwrap().split_whitespace();

    macro_rules! scan {
        ([$t:tt; $n:expr]) => ((0..$n).map(|_| scan!($t)).collect::<Vec<_>>());
        (($($t:tt),*)) => (($(scan!($t)),*));
        (Usize1) => (scan!(usize) - 1);
        (Bytes) => (scan!(String).into_bytes());
        ($t:ty) => (iter.next().unwrap().parse::<$t>().unwrap());
    }

    let (n, m) = scan!((usize, usize));
    let a = scan!([u32; n]);

    let mut g = vec![vec![]; n];
    for _ in 0..m {
        let (u, v) = scan!((Usize1, Usize1));
        g[u].push(v);
        g[v].push(u);
    }

    let k = scan!(usize);

    let mut lit = vec![false; n];
    for _ in 0..k {
        let b = scan!(Usize1);
        lit[b] = true;
    }

    let mut ord = (0..n).collect::<Vec<_>>();
    ord.sort_by_key(|&i| a[i]);

    let mut ans = vec![];
    for from in ord {
        if !lit[from] {
            continue;
        }
        ans.push(from);
        for &to in &g[from] {
            lit[to] ^= true;
        }
    }

    let stdout = std::io::stdout();
    let mut writer = std::io::BufWriter::new(stdout.lock());

    writeln!(writer, "{}", ans.len()).ok();
    for ans in ans {
        writeln!(writer, "{}", ans + 1).ok();
    }
}