#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let v = read_vec::<usize>();
    let (n, m) = (v[0], v[1]);
    let a = read_vec::<i64>();
    let mut edges = vec![];
    let mut g = vec![vec![]; n];
    for i in 0..m {
        let v = read_vec::<usize>();
        let (u, v) = (v[0] - 1, v[1] - 1);
        if a[u] < a[v] {
            edges.push((u, v));
            g[u].push(v);
        } else if a[u] > a[v] {
            edges.push((v, u));
            g[v].push(u);
        }
    }
    let k = read::<usize>();
    let v = read_vec::<usize>();
    let mut light = vec![false; n];
    for i in v {
        light[i - 1] = true;
    }
    let indexes = topological_sort(&edges, n).unwrap();

    let mut answers = vec![];
    for i in indexes {
        if light[i] {
            for &to in g[i].iter() {
                light[to] = !light[to];
            }
            answers.push(i);
        }
    }
    println!("{}", answers.len());
    for ans in answers {
        println!("{}", ans + 1);
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn topological_sort(edges: &Vec<(usize, usize)>, v: usize) -> Option<Vec<usize>> {
    let mut h = vec![0; v];
    let mut g = vec![Vec::new(); v];
    for &(s, t) in edges {
        g[s].push(t);
        h[t] += 1;
    }

    let mut st: std::collections::VecDeque<usize> = std::collections::VecDeque::new();
    for i in 0..v {
        if h[i] == 0 {
            st.push_back(i);
        }
    }

    let mut sorted_indexes = Vec::new();
    while !st.is_empty() {
        let i = st.pop_back().unwrap();
        sorted_indexes.push(i);
        for &j in g[i].iter() {
            h[j] -= 1;
            if h[j] == 0 {
                st.push_back(j);
            }
        }
    }
    if sorted_indexes.len() == v {
        Some(sorted_indexes)
    } else {
        None
    }
}