from queue import PriorityQueue

N,M,S,G = list(map(int, input().split(' ')))

C = []
for i in range(N):
    C.append([-1 for _ in range(N)])

for i in range(M):
    f,t,c = list(map(int, input().split(' ')))
    C[f][t] = c
    C[t][f] = c

D = []
for i in range(N):
    D.append(float('inf'))
D[S] = 0

P = []
for i in range(N):
    P.append(-1)

Q = PriorityQueue()
Q.put((0, S))

while not Q.empty():
    d, f = Q.get()
    if D[f] < d:
        continue
    for t, c in enumerate(C[f]):
        if c != -1:
            nc = D[f] + c 
            if nc < D[t]:
                D[t] = nc
                P[t] = f
                Q.put((D[t], t))
            elif nc == D[t]:
                P[t] = min(P[t], f)

s = S
t = G                
solution = []
while s != t:
    solution.insert(0, str(t))
    t = P[t]
solution.insert(0, str(S))

print(' '.join(solution))