from heapq import *
def f(n,m,p,q,t):
    to = {}
    for _ in range(m):
        a, b, c = map(int, input().split())
        to.setdefault(a, [])
        to.setdefault(b, [])
        to[a].append([b, c])
        to[b].append([a, c])

    sy = [[-1] * (n + 1) for _ in range(n + 1)]
    for s in range(1, n + 1):
        hp = []
        heappush(hp, [0, s])
        syr = sy[s]
        while hp:
            ji, g = heappop(hp)
            if syr[g] != -1: continue
            syr[g] = ji
            for ng, dt in to[g]:
                if syr[ng] != -1: continue
                heappush(hp, [ji + dt, ng])

    if sy[1][p] + sy[1][q] + sy[p][q] <= t:
        print(t)
    elif sy[1][p] * 2 > t or sy[1][q] * 2 > t:
        print(-1)
    else:
        mn = t
        syp=sy[p]
        syq=sy[q]
        sy1=sy[1]
        for w in range(1, n + 1):
            if w in [p, q]: continue
            for a in range(1, n + 1):
                if a in [p, q]: continue
                mx = max(syp[w] + syp[a], syq[w] + syq[a])
                if sy1[w] + mx + sy1[a] <= t:
                    mn = min(mn, mx)
        print(t - mn)

n,m,p,q,t=map(int,input().split())
f(n,m,p,q,t)