from heapq import *
def dijkstra(g,start):
    n = len(g)
    INF = 1<<61
    dist = [INF]*(n) #startからの最短距離
    #pending = n-1 #未確定の点の個数
    dist[start] = 0
    q = [(0,start)] #(そこまでの距離、点)
    while q:# and pending:
        dv,v = heappop(q)
        if dist[v] < dv: continue
        for to, cost in g[v]:
            if dv + cost < dist[to]:
                dist[to] = dv + cost
                heappush(q, (dist[to], to))
    return dist

n,m,s,goal = map(int,input().split())
g = [[] for _ in range(n)]
for _ in range(m):
    a,b,c = map(int,input().split())
    g[a].append((b,c))
    g[b].append((a,c))
    
dist = dijkstra(g,goal)

res = [s]
v = s
while v != goal:
    i = n+1
    for u,c in g[v]:
        if dist[v] == dist[u] + c:
            i = min(i,u)
    v = i
    res.append(v)
print(*res)