import sys
from heapq import heappush, heappop

inf = 1<<30

def solve():
    N, M, S, G = map(int, input().split())
    Adj = [[] for i in range(N)]

    for i in range(M):
        ai, bi, ci = map(int, input().split())
        Adj[ai].append((bi, ci))
        Adj[bi].append((ai, ci))

    d, p = dijkstra(N, Adj, G)

    path = [S]
    dfs(d, Adj, S, G, path)

    print(*path)

def dfs(d, Adj, v, G, path):
    if v == G:
        return

    nv = inf

    for u, c in Adj[v]:
        if d[v] - c == d[u] and u < nv:
            nv = u

    path.append(nv)
    dfs(d, Adj, nv, G, path)

def dijkstra(N, Adj, s):
    d = [inf] * N
    p = [inf] * N
    visited = [False] * N
    d[s] = 0
    p[s] = s
    pq = [(0, s)]

    for i in range(N):
        while pq:
            di, v = heappop(pq)

            if not visited[v] and di == d[v]:
                break

        visited[v] = True

        for u, c in Adj[v]:
            if d[v] + c < d[u]:
                d[u] = d[v] + c
                p[u] = v
                heappush(pq, (d[u], u))
            elif d[v] + c == d[u] and v < p[u]:
                p[u] = v

    return d, p

if __name__ == '__main__':
    solve()