#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
from heapq import heappop, heappush

# %%
N, M, S, G = map(int, readline().split())
m = map(int, read().split())
ABC = zip(m, m, m)

# %%
graph = [[] for _ in range(N)]
for a, b, c in ABC:
    graph[a].append((b, c))
    graph[b].append((a, c))

# %%
INF = 10 ** 15
dist = [INF] * N
dist[G] = 0
q = [G]
while q:
    x = heappop(q)
    dv, v = divmod(x, 1 << 20)
    if dv > dist[v]:
        continue
    for w, cost in graph[v]:
        dw = dv + cost
        if dw >= dist[w]:
            continue
        dist[w] = dw
        heappush(q, (dw << 20) + w)


# %%
path = [S]
while path[-1] != G:
    v = path[-1]
    for w, cost in sorted(graph[v]):
        if dist[v] - cost == dist[w]:
            path.append(w)
            break
print(*path)