from collections import defaultdict
from heapq import heappop, heappush

n, m, p, q, t = map(int, input().split())
p -= 1
q -= 1
G = defaultdict(list)
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))

INF = 10**18
C0 = [INF for _ in range(n)]
Cp = [INF for _ in range(n)]
Cq = [INF for _ in range(n)]
C0[0] = 0
Cp[p] = 0
Cq[q] = 0
H = [(0, 0)]
while H:
    cc, cp = heappop(H)
    if cc > Cp[cp]:
        continue
    for np, dc in G[cp]:
        nc = cc + dc
        if nc >= C0[np]:
            continue
        C0[np] = nc
        heappush(H, (nc, np))
H = [(0, p)]
while H:
    cc, cp = heappop(H)
    if cc > Cp[cp]:
        continue
    for np, dc in G[cp]:
        nc = cc + dc
        if nc >= Cp[np]:
            continue
        Cp[np] = nc
        heappush(H, (nc, np))
H = [(0, q)]
while H:
    cc, cp = heappop(H)
    if cc > Cq[cp]:
        continue
    for np, dc in G[cp]:
        nc = cc + dc
        if nc >= Cq[np]:
            continue
        Cq[np] = nc
        heappush(H, (nc, np))

ans = -1
if C0[p] + Cp[q] + Cq[0] <= t:
    ans = t
for i in range(n):
    for j in range(n):
        tt = C0[i] + max(Cp[i] + Cp[j], Cq[i] + Cq[j]) + C0[j]
        if tt > t:
            continue
        res = max(Cp[i] + Cp[j], Cq[i] + Cq[j])
        ans = max(ans, t - res)
print(ans)