import sys
input = sys.stdin.buffer.readline

def main():
    n, m, p, q, t = map(int, input().split())
    p -= 1
    q -= 1
    edge = [[] for _ in range(n)]
    for i in range(m):
        a, b, c = map(int, input().split())
        a, b = a-1, b-1
        edge[a].append((c, b))
        edge[b].append((c, a))

    import heapq
    INF = 10**18
    def dijkstra_heap(s, edge, n):
        d = [INF] * n
        used = [True] * n #True: not used
        d[s] = 0
        used[s] = False
        edgelist = []
        for e in edge[s]:
            heapq.heappush(edgelist,e)
        while len(edgelist):
            minedge = heapq.heappop(edgelist)
            if not used[minedge[1]]:
                continue
            v = minedge[1]
            d[v] = minedge[0]
            used[v] = False
            for e in edge[v]:
                if used[e[1]]:
                    heapq.heappush(edgelist,(e[0]+d[v],e[1]))
        return d

    d1 = dijkstra_heap(0, edge, n)
    dp = dijkstra_heap(p, edge, n)
    dq = dijkstra_heap(q, edge, n)

    if d1[p]+dp[q]+d1[q] <= t:
        print(t)
        exit()

    if 2*d1[p]> t or 2*d1[q] > t:
        print(-1)
        exit()

    ans = -1
    for r in range(n):
        temp = d1[r]+max(dp[r], dq[r])
        temp *= 2
        #print(r, temp)
        if temp <= t:
            temp2 = 2*d1[r]+t-temp
            ans = max(temp2, ans)

    print(ans)

if __name__ == '__main__':
    main()