import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int N = in.nextInt();
    int M = in.nextInt();
    int S = in.nextInt();
    int G = in.nextInt();
    Dijkstra d = new Dijkstra(N);
    for( int i = 0; i < M; i++ ) {
      int a = in.nextInt();
      int b = in.nextInt();
      int c = in.nextInt();
      d.addEdge(a,b,c);
      d.addEdge(b,a,c);
    }
    int[] dist = d.run(S);
    ArrayList<ArrayList<Edge>> g = new ArrayList<ArrayList<Edge>>();
    for( int i = 0; i < N; i++ ) {
      ArrayList<Edge> es = new ArrayList<Edge>();
      for( Edge e : d.g.get(i) ) {
        if( dist[e.from] + e.weight == dist[e.to] ) {
          es.add(e);
        }
      }
      g.add(es);
    }
    int v = S;
    while( v != G ) {
      System.out.print(v + " ");
      ArrayList<Edge> es = g.get(v);
      v = N;
      for( Edge e : es ) {
        if( !reachable(g,e.to,G) ) continue;
        v = Math.min(v, e.to);
      }
    }
    System.out.println(v);
  }

  static boolean reachable(ArrayList<ArrayList<Edge>> g, int s, int t){
    boolean[] vis = new boolean[g.size()];
    Deque<Integer> stack = new ArrayDeque<Integer>();
    stack.push(s);
    while(!stack.isEmpty()) {
      int v = stack.pop();
      if( v == t ) return true;
      if( vis[v] ) continue;
      vis[v] = true;
      for( Edge e : g.get(v) ) {
        stack.push(e.to);
      }
    }
    return false;
  }
}


class Edge implements Comparable<Edge>{
  int from;
  int to;
  int weight;

  public Edge(int from, int to, int weight) {
    this.from = from;
    this.to = to;
    this.weight = weight;
  }

  public int compareTo(Edge e) {
    if( this.weight < e.weight ) return -1;
    if( this.weight > e.weight ) return 1;
    if( this.from < e.from ) return -1;
    if( this.from > e.from ) return 1;
    if( this.to < e.to ) return -1;
    if( this.to > e.to ) return 1;
    return 0;
  }
}


class Dijkstra {
  int N;
  ArrayList<ArrayList<Edge>> g;

  public Dijkstra(int N) {
    this.N = N;
    g = new ArrayList<ArrayList<Edge>>();
    for( int i = 0; i < N; i++ ) {
      g.add(new ArrayList<Edge>());
    }
  }

  public void addEdge(Edge e) {
    g.get(e.from).add(e);
  }

  public void addEdge(int from, int to, int weight) {
    addEdge(new Edge(from, to, weight));
  }

  public int[] run(int start) {
    boolean[] vis = new boolean[N];
    int[] dist = new int[N];
    PriorityQueue<Edge> queue = new PriorityQueue<Edge>();
    queue.add(new Edge(start,0,0));
    while( !queue.isEmpty() ) {
      Edge e = queue.poll();
      if( vis[e.from] ) continue;
      vis[e.from] = true;
      dist[e.from] = e.weight;
      for( Edge ne : g.get(e.from) ) {
        if( !vis[ne.to] ) {
          queue.add(new Edge(ne.to,0,ne.weight + e.weight));
        }
      }
    }
    return dist;
  }
}