from heapq import heappush, heappop
INF = 10 ** 9
def dijkstra(s, n): # (始点, ノード数)
    dist = [INF] * n
    hq = [(0, s)] # (distance, node)
    dist[s] = 0
    seen = [False] * n # ノードが確定済みかどうか
    while hq:
        v = heappop(hq)[1] # ノードを pop する
        seen[v] = True
        for to, cost in adj[v]: # ノード v に隣接しているノードに対して
            if seen[to] == False and dist[v] + cost < dist[to]:
                dist[to] = dist[v] + cost
                heappush(hq, (dist[to], to))
    return dist

n,m,p,q,t = map(int,input().split())
p -= 1
q -= 1
adj = [[] for i in range(n)]

for i in range(m):
    a,b,c = map(int,input().split())
    a -= 1
    b -= 1
    adj[a].append([b,c])
    adj[b].append([a,c])

fst = dijkstra(0,n)
ans = t-2*max(fst[p],fst[q])
for i in range(1,n):
    rt = dijkstra(i,n)
    tmp = 2*fst[i]
    tmp += 2*max(rt[p],rt[q])
    if tmp <= t:
        ans = max(ans,t-tmp+2*fst[i])

print(max(ans,-1))