#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).unwrap();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().unwrap()
    };
}

fn main() {
    setup! { mut input: SplitWhitespace };

    let _n: usize = parse_next!(input);
    let m: usize = parse_next!(input);
    let s: usize = parse_next!(input);
    let g: usize = parse_next!(input);
    let mut f: Vec<usize> = vec![];
    let mut t: Vec<usize> = vec![];
    (0..m).for_each(|_| {
        f.push(parse_next!(input));
        t.push(parse_next!(input));
    });
    let u: usize = parse_next!(input);
    let i: Vec<usize> = (0..u).map(|_| parse_next!(input)).collect();

    let ans = match (|| {
        use std::collections::{HashSet, VecDeque};
        let mut queue = VecDeque::new();
        let mut visited = HashSet::new();
        let mut depth = 0;
        {
            let root = s;
            queue.push_back(root);
            visited.insert(root);
        }
        while !queue.is_empty() {
            for _ in 0..queue.len() {
                let from = match queue.pop_front() {
                    Some(value) => value,
                    None => unreachable!(),
                };
                if from == g {
                    return Some(depth);
                }
                let children = (0..m)
                    .filter(|&k| f[k] == from)
                    .map(|k| t[k])
                    .chain((0..m).filter(|&k| t[k] == from).map(|k| f[k]))
                    .filter(|&island| !i.contains(&island))
                    .collect::<Vec<_>>();
                for &to in children.iter() {
                    if visited.contains(&to) {
                        continue;
                    }
                    queue.push_back(to);
                    visited.insert(to);
                }
            }
            depth += 1;
        }
        None
    })() {
        Some(_) => "Yes",
        None => "No",
    };

    println!("{}", ans);
}