# 場合分けが甘い。
# 全部一緒と不可能のケースはOK
# 最初、途中まで一緒→最後一緒のパターンが甘い。
# 3頂点からの最短距離の組み合わせで行ける。
import sys
input = sys.stdin.buffer.readline

from heapq import heappush, heappop

n, m, p, q, t = map(int, input().split())
graph = [[] for _ in range(n + 1)]
for _ in range(m):
    a, b, c = map(int, input().split())
    graph[a].append((c, b))
    graph[b].append((c, a))
infi = 10 ** 20
dist = [infi] * (n + 1)
used = [False] * (n + 1)
edgelist = []


def dijkstra(start, dist):
    dist[start] = 0
    used[start] = True
    for cost, v in graph[start]:
        heappush(edgelist, (cost, v))
    while edgelist:
        cost, v = heappop(edgelist)
        if used[v]:
            continue
        used[v] = True
        dist[v] = min(cost, dist[v])
        for cost2, w in graph[v]:
            if used[w]:
                continue
            new_cost = cost2 + cost
            heappush(edgelist, (new_cost, w))
    return dist


calculated_dist1 = dijkstra(1, dist)
dist_ap = dist[p]
dist_aq = dist[q]

distp = [infi] * (n + 1)
used = [False] * (n + 1)
edgelist = []
calculated_distp = dijkstra(p, distp)
dist_pq = calculated_distp[q]

distq = [infi] * (n + 1)
used = [False] * (n + 1)
edgelist = []
calculated_distq = dijkstra(q, distq)

longer = max(dist_ap, dist_aq)
if dist_ap + dist_aq + dist_pq <= t:
    print(t)
elif 2 * longer > t:
    print(-1)
else:
    ans = 0
    for i in range(1, n + 1):
        for j in range(1, n + 1):
            total_p = (
                calculated_dist1[i]
                + calculated_distp[i]
                + calculated_distp[j]
                + calculated_dist1[j]
            )
            total_q = (
                calculated_dist1[i]
                + calculated_distq[i]
                + calculated_distq[j]
                + calculated_dist1[j]
            )
            bigger = max(total_p, total_q)
            if bigger <= t:
                ans = max(ans, calculated_dist1[i] + calculated_dist1[j] + t - bigger)
    print(ans)