from collections import defaultdict, deque
from heapq import heapify, heappop, heappush

n, m, s, g = map(int, input().split())
G = defaultdict(list)
for _ in range(m):
    a, b, c = map(int, input().split())
    G[a].append((b, c))
    G[b].append((a, c))
for i in range(n):
    G[i].sort(key=lambda x: x[0])
INF = 10**18
DP = [INF for _ in range(n)]
From = [-1 for _ in range(n)]
DP[g] = 0
H = [(0, g)]
while H:
    cc, cp = heappop(H)
    if cc > DP[cp]:
        continue
    for np, dc in G[cp]:
        nc = cc + dc
        if nc < DP[np]:
            DP[np] = nc
            From[np] = cp
            heappush(H, (nc, np))
        elif nc == DP[np]:
            From[np] = min(From[np], cp)

ANS = [s]
while ANS[-1] != g:
    cp = From[ANS[-1]]
    ANS.append(cp)
print(*ANS)