from heapq import heappop, heappush
INF = float('inf')

def dijkstra(s, n):
    dist = [INF] * n
    hq = [(0, s)] # (distance, node)
    dist[s] = 0
    seen = [False] * n
    while hq:
        dis, v = heappop(hq)
        if dist[v] < dis:
            continue
        seen[v] = True
        for to, cost in G[v]:
            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())
G = [list() for _ in range(N)]
for i in range(M):
    a, b, c = map(int, input().split())
    a-=1;b-=1
    G[a].append((b,c))
    G[b].append((a,c))

dis_0 = dijkstra(0,N)
dis_p = dijkstra(P-1,N)
dis_q = dijkstra(Q-1,N)
if max(dis_p[0]*2,dis_q[0]*2)>T:
    exit(print(-1))

if 2*min(dis_p[0],dis_q[0])+2*dis_p[Q-1]<=T or dis_p[0]+dis_q[0]+dis_p[Q-1]<=T:
    exit(print(T))

res = 0
for i in range(N):
    if 2*dis_0[i]+2*max(dis_p[i],dis_q[i])<=T:
        res = max(res,T-2*max(dis_p[i],dis_q[i]))
print(res)