from heapq import *
n,m,p,q,t=map(int,input().split())
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
    for w in range(1,n+1):
        if w in [p,q]:continue
        for a in range(1,n+1):
            mx=max(sy[w][p]+sy[p][a],sy[w][q]+sy[q][a])
            if sy[1][w]+mx+sy[a][1]<=t:
                mn=min(mn,mx)
    print(t-mn)