import java.util.PriorityQueue
import java.util.Scanner
import java.io.BufferedReader
import java.io.InputStreamReader

data class Edge(val v: Int, val w: Long)

val INF = 1e18.toLong()

fun dijkstra(g: Array<MutableList<Edge>>, s: Int): Array<Long> {
  data class State(val d: Long, val u: Int) : Comparable<State> {
    override operator fun compareTo(other: State): Int {
      return d.compareTo(other.d)
    }
  }
  var q: PriorityQueue<State> = PriorityQueue()
  val n = g.size
  var dist = Array(n, {INF})
  dist[s] = 0
  q.add(State(0, s))
  while (!q.isEmpty()) {
    val (d, u) = q.remove()
    if (d > dist[u]) continue
    for (e in g[u]) {
      if (dist[e.v] > dist[u] + e.w) {
        dist[e.v] = dist[u] + e.w
        q.add(State(dist[e.v], e.v))
      }
    }
  }
  return dist
}

class Reader {
  var buf: ByteArray = ByteArray(5000000)
  var k: Int = 0
  var n: Int = 0

  init {
    check()
  }

  private fun check() {
    if (k == n) {
      n = System.`in`.read(buf)
      k = 0
    }
  }

  private fun peek(): Byte {
    return buf[k]
  }

  private fun next() {
    k++
    check()
  }

  fun long(): Long {
    var ans: Long = 0
    while ('0'.toByte() > peek()) next()
    while ('0'.toByte() <= peek()) {
      ans = ans * 10 + (peek() - '0'.toLong())
      next() 
    }
    return ans
  }

  fun int(): Int {
    return long().toInt()
  }
}

fun main(args: Array<String>) {
  var r = Reader()
  
  val N = r.int()
  val M = r.int()
  val P = r.int() - 1
  val Q = r.int() - 1
  val T = r.long()
  var g = Array(N, {mutableListOf<Edge>()})
  repeat(M) {
    val u = r.int() - 1
    val v = r.int() - 1
    val w = r.long()
    g[u].add(Edge(v, w))
    g[v].add(Edge(u, w))
  }
  
  val start = System.currentTimeMillis()
  
  val d0 = dijkstra(g, 0)
  val dp = dijkstra(g, P)
  val dq = dijkstra(g, Q)
  val end = System.currentTimeMillis()
  var ans = -INF
  if (dp[0] + dp[Q] + dq[0] <= T) {
    ans = T
  }
  for (i in 0..N-1) {
    for (j in 0..N-1) {
      if (d0[i] + d0[j] + maxOf(dp[i] + dp[j], dq[i] + dq[j]) <= T) {
        ans = maxOf(ans, T - maxOf(dp[i] + dp[j], dq[i] + dq[j]))
      }
    }
  }
  
  System.err.println(end - start)
  if (ans < 0L) {
    println(-1)
  } else {
    println(ans)
  }
}