#include<bits/stdc++.h>
#define MAX ((int)1e9 + 5)
#define N ((int)5e4 + 5)
using namespace std;




vector < int > dijkstra(vector < vector < pair < int , int > > >& edg, int src , int n)
{
    vector < int > dis(n+1,MAX);

    dis[src] = 0;
    priority_queue < pair < int , int > > pqq;
    pqq.push({0,src}); /// (-distance,node)
    while(!pqq.empty()){
        pair < int , int > p = pqq.top();
        pqq.pop();
        int cur = p.second;
        if(-p.first > dis[cur]) continue;
        for(auto nxt:edg[cur]){
            int node = nxt.first , wgh = nxt.second;
            int val = dis[cur] + wgh;
            if(val < dis[node]){
                dis[node] = val;
                pqq.push({-val , node});
            }
        }
    } /// O(m * log(m))
    return dis;
}

void AddEdge(vector < pair < int , int > >& edg, int too , int cost)
{
    edg.push_back({too,cost});
}

int from[N] , too[N] , cost[N];

int main()
{
    /// problem H
    int t, caseNo = 1;
    cin>>t;
    while(t--){
        int n , m , src, des , money;
        cin>>n>>m>>src>>des>>money;
        vector < vector < pair < int , int > > > forEdg(n+1 , vector < pair < int , int > >() ) , revEdg(n+1, vector < pair < int , int > >() );

        for(int i = 1 ; i <= m ; i++){
            cin>>from[i]>>too[i]>>cost[i];
            AddEdge(forEdg[from[i]], too[i], cost[i]);
            AddEdge(revEdg[too[i]] , from[i] , cost[i]);
        }

        vector < int > disFromSrc = dijkstra(forEdg, src , n) , disFromDes = dijkstra(revEdg , des , n);
        int ans = -1;
        for(int i = 1 ; i <= m ; i++){
            int u = from[i] , v = too[i];
            if(disFromSrc[u] + cost[i] + disFromDes[v] <= money) ans = max(ans , cost[i]);
        }
        cout<<"Case "<<caseNo++<<": "<<ans<<endl;
    }
    return 0;
}