#include <bits/stdc++.h>
#include <unistd.h>

using namespace std;

#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}


typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const ll MOD = 1000000007;
//const ll MOD = 998244353;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { -1,0, 1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
// #define mp make_pair
//#define endl '\n'

vector<vector<pll> >  G;

ll n, m, p, q, t;

vl dijkstra(int s){
  priority_queue<pll, vector<pll>, greater<pll> > pq;
  int i;
  vl d(n, INF);
  d[s]=0;
  pq.push(make_pair(0,s));
  while(!pq.empty()){
    pll f=pq.top();
    pq.pop();
    int u=f.second;
    if(d[u]<f.first){
      continue;
    }
    for (i = 0; i < G[u].size(); i++) {
      int v=G[u][i].second;
      if (d[v] > d[u] + G[u][i].first) {
        d[v] = d[u] + G[u][i].first;
        pq.push(make_pair(d[v], v));
      }
    }
  }
  return d;
}


int main() {
  cin >> n >> m >> p >> q >> t;
  p--; q--;
  G.resize(n);
  rep (i, m) {
    ll u, v, c;
    cin >> u >> v >> c;
    u--; v--;
    G[u].push_back(pll(c, v));
    G[v].push_back(pll(c, u));
  }
  vl d0 = dijkstra(0);
  vl dp = dijkstra(p);
  vl dq = dijkstra(q);
  if (d0[p] + d0[q] + dp[q] <= t) {
    cout << t << endl;
    return 0;
  }
  if (2*d0[p] > t || 2*d0[q] > t) {
    cout << -1 << endl;
    return 0;
  }

  ll ans = 0;
  rep (u, n) {
    rep (v, n) {
      ll sum = 0, res = 0;
      sum += d0[u] + d0[v];
      sum += max(dp[u] + dp[v], dq[u] + dq[v]);
      res += max(dp[u] + dp[v], dq[u] + dq[v]);
      if (sum > t) continue;
      chmax(ans, t - res);
    }
  }
  cout << ans << endl;
}