import heapq


def dijkstra(start: int, graph: list) -> list:
    """dijkstra法: 始点startから各頂点への最短距離を求める
    計算量: O((E+V)logV)
    """
    INF = 10 ** 18
    n = len(graph)
    dist = [INF] * n
    dist[start] = 0
    q = [(0, start)] # q = [(startからの距離, 現在地)]
    while q:
        d, v = heapq.heappop(q)
        if dist[v] < d:
            continue
        for nxt_v, cost in graph[v]:
            if dist[v] + cost < dist[nxt_v]:
                dist[nxt_v] = dist[v] + cost
                heapq.heappush(q, (dist[nxt_v], nxt_v))
    return dist


n, m, s, g = map(int, input().split())
info = [list(map(int, input().split())) for i in range(m)]

graph = [[] for i in range(n)]
for a, b, cost in info:
    graph[a].append((b, cost))
    graph[b].append((a, cost))

dist = dijkstra(g, graph)

ans = [s]
v = s
while True:
    if v == g:
        break
    tmp_v = 10 ** 18
    for nxt_v, cost in graph[v]:
        if dist[v] == dist[nxt_v] + cost:
            tmp_v = min(tmp_v, nxt_v)
    v = tmp_v
    ans.append(v)
print(*ans)