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

import heapq
def dijkstra(s):
    inf = 10**18
    dist = [inf]*N
    dist[s] = 0
    h = []
    for e in E[s]:
        heapq.heappush(h, e)
    while h:
        temp = heapq.heappop(h)
        d = temp[0]
        v = temp[1]
        if dist[v] < d:
            continue
        dist[v] = d
        for e in E[v]:
            if dist[e[1]] < dist[v]+e[0]:
                continue
            heapq.heappush(h, (e[0]+d, e[1]))
    return dist

dist_0 = dijkstra(0)
dist_p = dijkstra(P-1)
dist_q = dijkstra(Q-1)
if dist_0[P-1]+dist_p[Q-1]+dist_q[0] <= T:
    ans = T
elif dist_0[P-1]*2 > T or dist_0[Q-1]*2 > T:
    ans = -1
else:
    ans = 0
    for i in range(N):
        if i == P-1 or i == Q-1:
            continue
        if (dist_0[i]+max(dist_p[i], dist_q[i]))*2 <= T:
            ans = max(ans, T-max(dist_p[i], dist_q[i])*2)

print(ans)