import heapq

def dijkstra(n, adj, start):
    INF = float('inf')
    dist = [INF] * (n + 1)
    dist[start] = 0
    heap = []
    heapq.heappush(heap, (0, start))
    while heap:
        current_dist, u = heapq.heappop(heap)
        if current_dist > dist[u]:
            continue
        for v, c in adj[u]:
            if dist[v] > dist[u] + c:
                dist[v] = dist[u] + c
                heapq.heappush(heap, (dist[v], v))
    return dist

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx]); idx +=1
    M = int(input[idx]); idx +=1
    P = int(input[idx]); idx +=1
    Q = int(input[idx]); idx +=1
    T = int(input[idx]); idx +=1
    
    adj = [[] for _ in range(N+1)]
    for _ in range(M):
        a = int(input[idx]); idx +=1
        b = int(input[idx]); idx +=1
        c = int(input[idx]); idx +=1
        adj[a].append((b, c))
        adj[b].append((a, c))
    
    d1 = dijkstra(N, adj, 1)
    d_p = dijkstra(N, adj, P)
    d_q = dijkstra(N, adj, Q)
    
    combined_time = d1[P] + d_p[Q] + d1[Q]
    if combined_time <= T:
        print(T)
        return
    
    max_overlap = -1
    for X in range(1, N+1):
        for Y in range(1, N+1):
            split_time = max(d_p[X] + d_p[Y], d_q[X] + d_q[Y])
            total_time = d1[X] + split_time + d1[Y]
            if total_time <= T:
                current_overlap = T - split_time
                if current_overlap > max_overlap:
                    max_overlap = current_overlap
    
    print(max_overlap if max_overlap != -1 else -1)

if __name__ == '__main__':
    main()