import java.util.ArrayList; import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.TreeSet; public class Main { private static void solve() { int n = ni(); int m = ni(); int p = ni(); int s = ni() - 1; int g = ni() - 1; int[] from = new int[m]; int[] to = new int[m]; for (int i = 0; i < m; i++) { from[i] = ni() - 1; to[i] = ni() - 1; } int[][] h = packU(n, from, to); int[][] ds = dijk(h, s); int[][] dg = dijk(h, g); List ret = new ArrayList<>(); outer: for (int i = 0; i < n; i++) { for (int j = 0; j < 2; j++) { for (int k = 0; k < 2; k++) { int d1 = ds[i][j]; int d2 = dg[i][k]; if (d1 + d2 <= p && (p - d1 - d2) % 2 == 0) { ret.add(i + 1); continue outer; } } } } if (ret.size() == 0) { out.println(-1); } else { out.println(ret.size()); for (int v : ret) { out.println(v); } } } public static int[][] dijk(int[][] g, int from) { int n = g.length; final int[][] td = new int[n][2]; for (int[] v : td) Arrays.fill(v, Integer.MAX_VALUE); TreeSet q = new TreeSet<>((a, b) -> { if (td[a[0]][a[1]] - td[b[0]][b[1]] != 0) return td[a[0]][a[1]] - td[b[0]][b[1]]; return a[0] == b[0] ? a[1] - b[1] : a[0] - b[0]; }); q.add(new int[] { from, 0 }); td[from][0] = 0; while (q.size() > 0) { int[] v = q.pollFirst(); int cur = v[0]; int cnt = v[1]; for (int nex : g[cur]) { int[] u = new int[] { nex, cnt }; int nd = td[cur][cnt] + 1; if (nd < td[nex][cnt]) { q.remove(u); td[nex][cnt] = nd; q.add(u); } if (cnt == 0) { int[] u2 = new int[] { nex, cnt + 1 }; int nd2 = td[cur][cnt] + 1; if (nd2 < td[nex][cnt + 1] && nd2 > td[nex][cnt]) { q.remove(u2); td[nex][cnt + 1] = nd; q.add(u2); } } } } return td; } public static int[][] packU(int n, int[] from, int[] to) { return packU(n, from, to, from.length); } public static int[][] packU(int n, int[] from, int[] to, int sup) { int[][] g = new int[n][]; int[] p = new int[n]; for (int i = 0; i < sup; i++) p[from[i]]++; for (int i = 0; i < sup; i++) p[to[i]]++; for (int i = 0; i < n; i++) g[i] = new int[p[i]]; for (int i = 0; i < sup; i++) { g[from[i]][--p[from[i]]] = to[i]; g[to[i]][--p[to[i]]] = from[i]; } return g; } public static void main(String[] args) { new Thread(null, new Runnable() { @Override public void run() { long start = System.currentTimeMillis(); String debug = args.length > 0 ? args[0] : null; if (debug != null) { try { is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug)); } catch (Exception e) { throw new RuntimeException(e); } } reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768); solve(); out.flush(); tr((System.currentTimeMillis() - start) + "ms"); } }, "", 64000000).start(); } private static java.io.InputStream is = System.in; private static java.io.PrintWriter out = new java.io.PrintWriter(System.out); private static java.util.StringTokenizer tokenizer = null; private static java.io.BufferedReader reader; public static String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) { try { tokenizer = new java.util.StringTokenizer(reader.readLine()); } catch (Exception e) { throw new RuntimeException(e); } } return tokenizer.nextToken(); } private static double nd() { return Double.parseDouble(next()); } private static long nl() { return Long.parseLong(next()); } private static int[] na(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) a[i] = ni(); return a; } private static char[] ns() { return next().toCharArray(); } private static long[] nal(int n) { long[] a = new long[n]; for (int i = 0; i < n; i++) a[i] = nl(); return a; } private static int[][] ntable(int n, int m) { int[][] table = new int[n][m]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[i][j] = ni(); } } return table; } private static int[][] nlist(int n, int m) { int[][] table = new int[m][n]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[j][i] = ni(); } } return table; } private static int ni() { return Integer.parseInt(next()); } private static void tr(Object... o) { if (is != System.in) System.out.println(java.util.Arrays.deepToString(o)); } }