import heapq
import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)
inf = 10**18


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


def dijkstra(start):
    dist = [inf] * N
    dist[start] = 0
    que = [(0, start)]
    while que:
        ds, s = heapq.heappop(que)
        if dist[s] < ds:
            continue
        for t, dt in G[s]:
            if dist[t] > ds + dt:
                dist[t] = ds + dt
                heapq.heappush(que, (ds + dt, t))
    return dist


dist0 = dijkstra(0)
distP = dijkstra(P)
distQ = dijkstra(Q)

if dist0[P] + dist0[Q] + distP[Q] <= T:
    print(T)
    exit()

if 2 * max(dist0[P], dist0[Q]) > T:
    print(-1)
    exit()

ans = 0
for i in range(N):
    go = dist0[i]
    to_p = distP[i]
    to_q = distQ[i]
    for j in range(N):
        from_p = distP[j]
        from_q = distQ[j]
        back = dist0[j]
        separate = max(to_p + from_p, to_q + from_q)
        if go + back + separate <= T:
            ans = max(ans, T - separate)

print(ans)