from heapq import *
from collections import defaultdict
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def SI(): return sys.stdin.readline()[:-1]

# 同じ距離のときにルートの辞書順が小さい方を選べばいいので
# キーの２番目にルートを文字列でいれておいてダイクストラ
def main():
    n, m, s, g = MI()
    to = defaultdict(list)
    for _ in range(m):
        a, b, c = MI()
        to[a].append([b, c])
        to[b].append([a, c])
    hp = []
    heappush(hp, [0, str(s), s])
    fin = [False] * n
    while hp:
        d, r, u = heappop(hp)
        if u == g:
            r = list(r)
            print(*r)
            exit()
        if fin[u]: continue
        fin[u] = True
        for v, c in to[u]:
            if fin[v]: continue
            heappush(hp, [d + c, r + str(v), v])

main()