using System; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Globalization; using System.IO; using System.Text; using System.Linq; using E = System.Linq.Enumerable; using System.Threading; using System.Numerics; internal partial class Solver { public void Run() { var n = ni(); var m = ni(); var p = ni(); var S = ni() - 1; var G = ni() - 1; var adj = Enumerable.Range(0, n).Select(_ => new List()).ToArray(); for (int i = 0; i < m; i++) { var u = ni() - 1; var v = ni() - 1; adj[u].Add(v); adj[v].Add(u); } var bfs1 = BFS(adj, S); var bfs2 = BFS(adj, G); var ans = new List(); var inf = (int)1e8; if (bfs1[G, 0] >= inf && bfs1[G, 1] >= inf) { cout.WriteLine(-1); return; } for (int i = 0; i < n; i++) { bool found = false; for (int pi = 0; pi < 2 && !found; pi++) { for (int qi = 0; qi < 2 && !found; qi++) { var d1 = bfs1[i, pi]; if (d1 >= inf) continue; var d2 = bfs2[i, qi]; if (d2 >= inf) continue; var rem = p - d1 - d2; if (rem >= 0 && rem % 2 == 0) { ans.Add(i + 1); found = true; break; } } } } cout.WriteLine(ans.Count); cout.WriteLine(ans.JoinToString("\n")); } int[,] BFS(List[] adj, int start) { var queue = new Queue(); queue.Enqueue(start); queue.Enqueue(0); var n = adj.Length; var dist = new int[n, 2]; var inf = (int)1e8; for (int i = 0; i < n; i++) { dist[i, 0] = dist[i, 1] = inf; } while (queue.Count > 0) { var now = queue.Dequeue(); var step = queue.Dequeue(); if (step >= dist[now, step % 2]) continue; dist[now, step % 2] = step; foreach (var next in adj[now]) { queue.Enqueue(next); queue.Enqueue(step + 1); } } return dist; } } // PREWRITEN CODE BEGINS FROM HERE static public class StringExtensions { static public string JoinToString(this IEnumerable source, string separator = " ") { return string.Join(separator, source); } } internal partial class Solver : Scanner { static readonly int? StackSizeInMebiByte = null; //50; public static void StartAndJoin(Action action, int maxStackSize) { var thread = new Thread(new ThreadStart(action), maxStackSize); thread.Start(); thread.Join(); } public static void Main() { #if LOCAL byte[] inputBuffer = new byte[1000000]; var inputStream = Console.OpenStandardInput(inputBuffer.Length); using (var reader = new StreamReader(inputStream, Console.InputEncoding, false, inputBuffer.Length)) { Console.SetIn(reader); new Solver(Console.In, Console.Out).Run(); } #else Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }); if (StackSizeInMebiByte.HasValue) { StartAndJoin(() => new Solver(Console.In, Console.Out).Run(), StackSizeInMebiByte.Value * 1024 * 1024); } else { new Solver(Console.In, Console.Out).Run(); } Console.Out.Flush(); #endif } #pragma warning disable IDE0052 private readonly TextReader cin; private readonly TextWriter cout; private readonly TextWriter cerr; #pragma warning restore IDE0052 public Solver(TextReader reader, TextWriter writer) : base(reader) { cin = reader; cout = writer; cerr = Console.Error; } public Solver(string input, TextWriter writer) : this(new StringReader(input), writer) { } #pragma warning disable IDE1006 #pragma warning disable IDE0051 private int ni() { return NextInt(); } private int[] ni(int n) { return NextIntArray(n); } private long nl() { return NextLong(); } private long[] nl(int n) { return NextLongArray(n); } private double nd() { return NextDouble(); } private double[] nd(int n) { return NextDoubleArray(n); } private string ns() { return Next(); } private string[] ns(int n) { return NextArray(n); } #pragma warning restore IDE1006 #pragma warning restore IDE0051 } #if DEBUG internal static class LinqPadExtension { public static string TextDump(this T obj) { if (obj is IEnumerable) return (obj as IEnumerable).Cast().JoinToString().Dump(); else return obj.ToString().Dump(); } public static T Dump(this T obj) { return LINQPad.Extensions.Dump(obj); } } #endif public class Scanner { private readonly TextReader Reader; private readonly CultureInfo ci = CultureInfo.InvariantCulture; private readonly char[] buffer = new char[2 * 1024]; private int cursor = 0, length = 0; private string Token; private readonly StringBuilder sb = new StringBuilder(1024); public Scanner() : this(Console.In) { } public Scanner(TextReader reader) { Reader = reader; } public int NextInt() { return checked((int)NextLong()); } public long NextLong() { var s = Next(); long r = 0; int i = 0; bool negative = false; if (s[i] == '-') { negative = true; i++; } for (; i < s.Length; i++) { r = r * 10 + (s[i] - '0'); #if DEBUG if (!char.IsDigit(s[i])) throw new FormatException(); #endif } return negative ? -r : r; } public double NextDouble() { return double.Parse(Next(), ci); } public string[] NextArray(int size) { string[] array = new string[size]; for (int i = 0; i < size; i++) { array[i] = Next(); } return array; } public int[] NextIntArray(int size) { int[] array = new int[size]; for (int i = 0; i < size; i++) { array[i] = NextInt(); } return array; } public long[] NextLongArray(int size) { long[] array = new long[size]; for (int i = 0; i < size; i++) { array[i] = NextLong(); } return array; } public double[] NextDoubleArray(int size) { double[] array = new double[size]; for (int i = 0; i < size; i++) { array[i] = NextDouble(); } return array; } public string Next() { if (Token == null) { if (!StockToken()) { throw new Exception(); } } var token = Token; Token = null; return token; } public bool HasNext() { if (Token != null) { return true; } return StockToken(); } private bool StockToken() { while (true) { sb.Clear(); while (true) { if (cursor >= length) { cursor = 0; if ((length = Reader.Read(buffer, 0, buffer.Length)) <= 0) { break; } } var c = buffer[cursor++]; if (33 <= c && c <= 126) { sb.Append(c); } else { if (sb.Length > 0) break; } } if (sb.Length > 0) { Token = sb.ToString(); return true; } return false; } } }