import heapq

def main():
    N, M, S, G = map(int, input().split())
    edges = [[] for _ in range(N)]
    for _ in range(M):
        a, b, c = map(int, input().split())
        edges[a].append((b, c))
        edges[b].append((a, c))
    
    INF = float('inf')
    dist = [INF] * N
    prev = [-1] * N
    dist[S] = 0
    heap = []
    heapq.heappush(heap, (0, S))
    
    while heap:
        current_dist, u = heapq.heappop(heap)
        if current_dist > dist[u]:
            continue
        for v, c in edges[u]:
            new_dist = current_dist + c
            if new_dist < dist[v]:
                dist[v] = new_dist
                prev[v] = u
                heapq.heappush(heap, (new_dist, v))
            elif new_dist == dist[v]:
                if prev[v] == -1 or u < prev[v]:
                    prev[v] = u
                    heapq.heappush(heap, (new_dist, v))
    
    path = []
    current = G
    while current != S:
        path.append(current)
        current = prev[current]
        if current == -1:
            break  # This case won't occur as per problem constraints
    path.append(S)
    path = path[::-1]
    print(' '.join(map(str, path)))

if __name__ == "__main__":
    main()