/* -*- coding: utf-8 -*-
 *
 * 848.cc:  No.848 なかよし旅行 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 3000;
const int INF = 1 << 30;

/* typedef */

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<pii> vpii;

/* global variables */

vpii nbrs[MAX_N];
int dps[MAX_N], dqs[MAX_N], drs[MAX_N];

/* subroutines */

void calc_ds(int n, int ds[], int st) {
  fill(ds, ds + n, INF);
  ds[st] = 0;

  priority_queue<pii> q;
  q.push(pii(0, st));

  while (! q.empty()) {
    pii u = q.top(); q.pop();
    int ud = -u.first, &ui = u.second;
    vpii &nbru = nbrs[ui];
    for (vpii::iterator vit = nbru.begin(); vit != nbru.end(); vit++) {
      int &vi = vit->first, vd = ud + vit->second;
      if (ds[vi] > vd) {
	ds[vi] = vd;
	q.push(pii(-vd, vi));
      }
    }
  }
}

/* main */

int main() {
  int n, m, p, q, t;
  scanf("%d%d%d%d%d", &n, &m, &p, &q, &t);
  p--, q--;

  for (int i = 0; i < m; i++) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    a--, b--;
    nbrs[a].push_back(pii(b, c));
    nbrs[b].push_back(pii(a, c));
  }

  calc_ds(n, dps, p);
  calc_ds(n, dqs, q);
  calc_ds(n, drs, 0);

  int maxw = -1;
  if (drs[p] < INF && dps[q] < INF && dqs[0] < INF) {
    ll s = (ll)drs[p] + dps[q] + dqs[0];
    if (s <= t) maxw = t;
  }

  for (int i = 0; i < n; i++) {
    if (drs[i] < INF && dps[i] < INF && dqs[i] < INF) {
      int d = max(dps[i], dqs[i]), w = t - d * 2;
      ll s = (ll)(drs[i] + d) * 2;
      if (s <= t && maxw < w) maxw = w;
    }

    if (drs[i] < INF && dps[i] < INF && dqs[i] < INF &&
	dps[0] < INF && dqs[0] < INF) {
      int d = max(dps[i] + dps[0], dqs[i] + dqs[0]), w = t - d;
      ll s = (ll)drs[i] + d;
      if (s <= t && maxw < w) maxw = w;
    }
  }
  
  printf("%d\n", maxw);
  return 0;
}