import java.util.Arrays; import java.util.Comparator; import java.util.TreeSet; public class Main { private static void solve() { int n = ni(); int m = ni(); int p = ni() - 1; int q = ni() - 1; int t = ni(); int[] from = new int[m]; int[] to = new int[m]; int[] w = new int[m]; for (int i = 0; i < m; i++) { from[i] = ni() - 1; to[i] = ni() - 1; w[i] = ni(); } int[][][] g = packWU(n, from, to, w); long[] ds = dijk(g, 0); long[] dp = dijk(g, p); long[] dq = dijk(g, q); if (ds[p] + dp[q] + dq[0] <= t) { System.out.println(t); return; } long ret = -1; for (int i = 0; i < n; i++) { long total = ds[i] * 2 + Math.max(dp[i], dq[i]) * 2; if (total > t) continue; ret = Math.max(ret, t - Math.max(dp[i], dq[i]) * 2); } System.out.println(ret); } public static long[] dijk(int[][][] g, int from) { int n = g.length; final long[] td = new long[n]; Arrays.fill(td, Long.MAX_VALUE); TreeSet q = new TreeSet(new Comparator(){ public int compare(Integer a, Integer b) { if(td[a] - td[b] != 0)return Long.signum(td[a] - td[b]); return a - b; } }); q.add(from); td[from] = 0; while(q.size() > 0){ int cur = q.pollFirst(); for(int i = 0;i < g[cur].length;i++){ int next = g[cur][i][0]; long nd = td[cur] + g[cur][i][1]; if(nd < td[next]){ q.remove(next); td[next] = nd; q.add(next); } } } return td; } public static int[][][] packWU(int n, int[] from, int[] to, int[] w) { int[][][] g = new int[n][][]; int[] p = new int[n]; for (int f : from) p[f]++; for (int t : to) p[t]++; for (int i = 0; i < n; i++) g[i] = new int[p[i]][2]; for (int i = 0; i < from.length; i++) { --p[from[i]]; g[from[i]][p[from[i]]][0] = to[i]; g[from[i]][p[from[i]]][1] = w[i]; --p[to[i]]; g[to[i]][p[to[i]]][0] = from[i]; g[to[i]][p[to[i]]][1] = w[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)); } }