#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
import numpy as np
from scipy.sparse import csr_matrix
from scipy.sparse.csgraph import dijkstra

# %%
N, M, P, Q, T = map(int, readline().split())
ABC = np.array(read().split(), np.int64)
A = ABC[::3]
B = ABC[1::3]
C = ABC[2::3]

# %%
G = csr_matrix((C, (A, B)), (N + 1, N + 1))
D = dijkstra(G, directed=False, indices=[1, P, Q])
D[D == np.inf] = T + 100
D1, DP, DQ = D.astype(np.int64)


# %%
def solve(D1, DP, DQ):
    if D1[P] + DP[Q] + D1[Q] <= T:
        return T
    APB = np.add.outer(DP, DP)
    AQB = np.add.outer(DQ, DQ)
    AB = np.maximum(APB, AQB)
    t = np.add.outer(D1, D1) + AB
    can_goal = (t <= T)
    if not np.any(can_goal):
        return - 1
    else:
        return T - np.min(AB[can_goal])


# %%
print(solve(D1, DP, DQ))