from heapq import heappush, heappop
import sys
readline = sys.stdin.readline
inf = float('inf')
 
 
def dijstra(s, g, N):
    # ゴールがない場合はg=-1とする。
 
    def cost(v, m):
        return v * N + m
 
    dist = [inf] * N
    mindist = [inf] * N
    seen = [False] * N
    Q = [(cost(0, s), -1)]
    while Q:
        d, p = heappop(Q)
        c, m = divmod(d, N)
        if seen[m]:
            continue
        seen[m] = True
        dist[m] = c
        if m == g:
            return dist
 
        # ------heapをアップデートする。--------
        for u, C in G[m]:
            if seen[u]:
                continue
            newdist = dist[m] + C
 
            # ------------------------------------
            if newdist >= mindist[u]:
                continue
 
            mindist[u] = newdist
            heappush(Q, (cost(newdist, u), m))
    return dist

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

D0 = dijstra(0, -1, N)
DP, DQ = dijstra(P, -1, N), dijstra(Q, -1, N)
ans = -inf
if min(D0[P] + DP[Q] + DQ[0], D0[Q] + DQ[P] + DP[0]) <= T:
    print(T)
    exit()

for s in range(N):
    for t in range(N):
        v1 = max(DP[s] + DP[t], DQ[s] + DQ[t])
        v2 = D0[s] + D0[t]
        if v1 + v2 > T:
            continue
        ans = max(ans, T - v1)

print(ans) if ans >= 0 else print(-1)