import sys
readline = sys.stdin.readline

N,M,P,Q,T = map(int,readline().split())
P -= 1
Q -= 1
G = [[] for i in range(N)]
for _ in range(M):
    a,b,c = map(int,readline().split())
    G[a - 1].append([b - 1, c])
    G[b - 1].append([a - 1, c])
    
INF = 1 << 60
import heapq as hq
def get_dist_from(x):
    dist = [INF] * N
    q = []
    hq.heappush(q, (0, x))
    while q:
        d, v = hq.heappop(q)
        if dist[v] != INF:
            continue
        dist[v] = d
        for child, c in G[v]:
            if dist[child] != INF:
                continue
            hq.heappush(q, (d + c, child))
    return dist
    
dist_from_0 = get_dist_from(0)
dist_from_P = get_dist_from(P)
dist_from_Q = get_dist_from(Q)


if dist_from_0[P] + dist_from_Q[P] + dist_from_0[Q] <= T:
    print(T)
    exit(0)
    
if max(dist_from_0[P], dist_from_0[Q]) * 2 > T:
    print(-1)
    exit(0)

ans = 0
for v in range(N):
    # vまで一緒に行動して、以後別行動パターン
    time = dist_from_0[v] + max(dist_from_Q[v] + dist_from_Q[0], dist_from_P[v] + dist_from_P[0])
    if time <= T:
        without = max(dist_from_Q[v] + dist_from_Q[0], dist_from_P[v] + dist_from_P[0])
        stay = T - without
        ans = max(ans, stay)

    # vまで一緒に行動、P,Qを訪れて、またvに合流するパターン
    time = dist_from_0[v] * 2 + max(dist_from_P[v] * 2, dist_from_Q[v] * 2)
    if time <= T:
        stay = T - max(dist_from_P[v] * 2, dist_from_Q[v] * 2)
        ans = max(ans, stay)
print(ans)