from heapq import *
N,M,P,Q,T = map(int,input().split())
UV = [list(map(int,input().split())) for _ in range(M)]
E = [[] for _ in range(N)]
P -= 1
Q -= 1
for u, v, c in UV:
    u -= 1
    v -= 1
    E[u].append((v,c))
    E[v].append((u,c))

INF = 10 ** 13 # N * maxコストくらいで設定

#普通のダイクストラ
def dijkstra(x):
    D = [INF] * N
    D[x] = 0
    q = [(0, x)]
    while q:
        d, u = heappop(q)
        #下のifでTLE解消することがある
        if d > D[u]: continue
        for i in E[u]:
            a,b = i
            if D[a] > D[u] + b:
                D[a] = D[u] + b
                heappush(q, (D[a], a))
    return D

D0 = dijkstra(0)
DP = dijkstra(P)
DQ = dijkstra(Q)

d0p = D0[P]
d0q = D0[Q]
dpq = DP[Q]

if d0p + d0q +dpq <= T:
    print(T)
    exit()
ans = -1
for i in range(N):
    d0i = D0[i]
    dip = DP[i]
    diq = DQ[i]
    mdi = max(dip, diq)
    if (d0i + mdi) * 2 <= T:
        ans = max(ans,T - mdi * 2)
print(ans)