use std::collections::VecDeque;

fn main() {
    let (n, m, p) = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse::<usize>().unwrap(),
            iter.next().unwrap().parse::<usize>().unwrap(),
            iter.next().unwrap().parse::<usize>().unwrap(),
        )
    };
    let (s, g) = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let mut iter = line.split_whitespace();
        (
            iter.next().unwrap().parse::<usize>().unwrap() - 1,
            iter.next().unwrap().parse::<usize>().unwrap() - 1,
        )
    };
    let uv: Vec<_> = (0..m)
        .map(|_| {
            let mut line = String::new();
            std::io::stdin().read_line(&mut line).unwrap();
            let mut iter = line.split_whitespace();
            (
                iter.next().unwrap().parse::<usize>().unwrap() - 1,
                iter.next().unwrap().parse::<usize>().unwrap() - 1,
            )
        })
        .collect();

    let mut graph = vec![vec![]; n];
    for &(a, b) in &uv {
        graph[a].push(b);
        graph[b].push(a);
    }
    graph.iter_mut().for_each(|x| x.sort_unstable());

    let mut distances: Vec<Vec<Option<usize>>> = vec![vec![None; 2]; n];
    distances[s][0] = Some(0);
    let mut queue = VecDeque::from(vec![s]);

    while let Some(cur) = queue.pop_front() {
        for &next in &graph[cur] {
            for cur_parity in 0..2 {
                let next_parity = 1 - cur_parity;

                if let Some(cur_dist) = distances[cur][cur_parity] {
                    let next_dist = &mut distances[next][next_parity];

                    if next_dist.is_none() || cur_dist + 1 < next_dist.unwrap() {
                        *next_dist = Some(cur_dist + 1);
                        queue.push_back(next);
                    }
                }
            }
        }
    }

    let mut rev_distances: Vec<Vec<Option<usize>>> = vec![vec![None; 2]; n];
    rev_distances[g][0] = Some(0);
    let mut queue = VecDeque::from(vec![g]);

    while let Some(cur) = queue.pop_front() {
        for &next in &graph[cur] {
            for cur_parity in 0..2 {
                let next_parity = 1 - cur_parity;

                if let Some(cur_dist) = rev_distances[cur][cur_parity] {
                    let next_dist = &mut rev_distances[next][next_parity];

                    if next_dist.is_none() || cur_dist + 1 < next_dist.unwrap() {
                        *next_dist = Some(cur_dist + 1);
                        queue.push_back(next);
                    }
                }
            }
        }
    }

    let mut flags = vec![false; n];
    let p_parity = p % 2;
    for i in 0..n {
        for parity1 in 0..2 {
            let parity2 = (p_parity + parity1) % 2;
            if let (Some(dist1), Some(dist2)) = (distances[i][parity1], rev_distances[i][parity2]) {
                if dist1 + dist2 <= p {
                    flags[i] = true;
                }
            }
        }
    }

    let ans_num = flags.iter().filter(|&&x| x).count();

    if ans_num == 0 {
        println!("-1");
        std::process::exit(0);
    }

    println!("{}", ans_num);
    for i in (0..n).filter(|&i| flags[i]) {
        println!("{}", i + 1);
    }
}