//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 より
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

use std::io::Write;

fn run() {
    input! {
        n: usize,
        m: usize,
        p: usize,
        st: (usize1, usize1),
        e: [(usize1, usize1); m],
    }
    let mut g = vec![vec![]; n];
    for (a, b) in e {
        g[a].push(b);
        g[b].push(a);
    }
    let mut dp = vec![vec![p + 1; n]; 2];
    dp[0][st.0] = 0;
    let mut q = std::collections::VecDeque::new();
    q.push_back((0, st.0));
    while let Some((s, v)) = q.pop_front() {
        let d = dp[s][v] + 1;
        let s = s ^ 1;
        for &u in g[v].iter() {
            if d < dp[s][u] {
                dp[s][u] = d;
                q.push_back((s, u));
            }
        }
    }
    if dp[p % 2][st.1] > p {
        println!("-1");
        return;
    }
    let rem = (p - dp[p % 2][st.1]) / 2;
    let mut used = vec![vec![false; n]; 2];
    used[p % 2][st.1] = true;
    let mut a = vec![false; n];
    let mut q = std::collections::VecDeque::new();
    q.push_back((p % 2, st.1));
    while let Some((s, v)) = q.pop_front() {
        a[v] = true;
        let d = dp[s][v] - 1;
        let s = s ^ 1;
        for &u in g[v].iter() {
            if !used[s][u] && dp[s][u] == d {
                used[s][u] = true;
                q.push_back((s, u));
            }
        }
    }
    let mut dp = vec![rem + 1; n];
    let mut q = std::collections::VecDeque::new();
    for (i, a) in a.iter().enumerate() {
        if *a {
            dp[i] = 0;
            q.push_back(i);
        }
    }
    while let Some(v) = q.pop_front() {
        let d = dp[v] + 1;
        for &u in g[v].iter() {
            if dp[u] > d {
                dp[u] = d;
                q.push_back(u);
            }
        }
    }
    let out = std::io::stdout();
    let mut out = std::io::BufWriter::new(out.lock());
    let ans = dp.iter().filter(|p| **p <= rem).count();
    writeln!(out, "{}", ans).ok();
    for (i, d) in dp.iter().enumerate() {
        if *d <= rem {
            writeln!(out, "{}", i + 1).ok();
        }
    }
}

fn main() {
    run();
}