import heapq


def dijkstra(s, graph):
    n = len(graph)-1
    dist = [float("inf") for i in range(n+1)]
    dist[s] = 0
    pq = []
    heapq.heapify(pq)
    heapq.heappush(pq, (0, s))
    while pq:
        mini_dis, node = heapq.heappop(pq)
        if dist[node] < mini_dis:
            continue
        for w, point in graph[node]:
            if dist[point] < w:
                continue
            newlen = dist[node]+w
            if newlen < dist[point]:
                heapq.heappush(pq, (newlen, point))
                dist[point] = newlen
    return dist


N, M, P, Q, T = map(int, input().split())
graph = [[] for i in range(N+1)]
for i in range(M):
    a, b, c = map(int, input().split())
    graph[a].append((c, b))
    graph[b].append((c, a))


A = dijkstra(1, graph)
B = dijkstra(P, graph)
C = dijkstra(Q, graph)


if max(2*A[P], 2*A[Q]) > T:
    print(-1)
    exit()

if (A[P]+A[Q]+C[P]) <= T:
    print(T)
    exit()
else:
    ans = 0
    for x in range(1, N+1):
        for y in range(1, N+1):
            if A[x]+B[x]+B[y]+A[y] <= T and A[x]+C[x]+C[y]+A[y] <= T:
                ans = max(ans,T-max(B[x]+B[y],C[x]+C[y]))
    print(ans)