use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let m: usize = itr.next().unwrap().parse().unwrap();

    let mut ai = Vec::new();
    let mut a = Vec::new();
    for i in 0..n {
        let x: usize = itr.next().unwrap().parse::<usize>().unwrap();
        a.push(x);
        ai.push((x, i));
    }
    ai.sort();

    let mut g: Vec<Vec<usize>> = vec![Vec::new(); n];

    for _ in 0..m {
        let u: usize = itr.next().unwrap().parse::<usize>().unwrap() - 1;
        let v: usize = itr.next().unwrap().parse::<usize>().unwrap() - 1;
        g[u].push(v);
        g[v].push(u);
    }

    let mut on: Vec<usize> = vec![0; n];
    let k: usize = itr.next().unwrap().parse().unwrap();
    for _ in 0..k {
        let b: usize = itr.next().unwrap().parse::<usize>().unwrap() - 1;
        on[b] = 1;
    }

    let mut ans = Vec::new();
    for &(_, i) in ai.iter() {
        if on[i] == 0 {
            continue;
        }
        ans.push(i + 1);
        on[i] = 0;
        for &ni in g[i].iter() {
            if a[i] < a[ni] {
                on[ni] ^= 1;
            }
        }
    }
    let mut ok = true;
    for i in 0..n {
        ok &= on[i] == 0;
    }
    if ok {
        println!("{}", ans.len());
        for &x in ans.iter() {
            println!("{}", x);
        }
    } else {
        println!("-1")
    }
}