import java.util.*;
import java.io.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class No160 {

    static final InputStream in = System.in;
    static final PrintWriter out = new PrintWriter(System.out,false);

    static void solve(){
        int n = nextInt();
        int m = nextInt();
        int s = nextInt();
        int g = nextInt();
        int[] n1 = new int[m];
        int[] n2 = new int[m];
        int[] cost = new int[m];
        for (int i=0; i<m; i++) {
            n1[i] = nextInt();
            n2[i] = nextInt();
            cost[i] = nextInt();
        }

        int[][][] graph = toAdjacencyList(n,n1,n2,cost);
        int[] d = dijkstra(graph,g);

        ArrayList<Integer> list = new ArrayList<Integer>();
        list.add(s);
        int cur = s;
        while (cur != g) {
            int next = Integer.MAX_VALUE/2;
            for (int[] to : graph[cur])
                if (d[cur] == d[to[0]] + to[1])
                    next = min(next,to[0]);

            list.add(next);
            cur = next;
        }

        for (int i=0; i<list.size()-1; i++)
            out.print(list.get(i)+" ");
        out.println(list.get(list.size()-1));
    }

    static int[] dijkstra(int[][][] g, int from){
        int n = g.length;
        final int[] d = new int[n];
        fill(d,Integer.MAX_VALUE);
        TreeSet<Integer> que = new TreeSet<Integer>(new Comparator<Integer>(){
            public int compare(Integer a, Integer b){
                if (d[a]-d[b] != 0) return d[a] - d[b];
                return a - b;
            }
        });
        que.add(from);
        d[from] = 0;
    
        while (!que.isEmpty()) {
            int cur = que.pollFirst();
    
            for (int i=0; i<g[cur].length; i++) {
                int next = g[cur][i][0];
                int cost = d[cur] + g[cur][i][1];
                if (cost < d[next]) {
                    que.remove(next);
                    d[next] = cost;
                    que.add(next);
                }
            }
        }
    
        return d;
    }

    static int[][][] toAdjacencyList(int n,int[] from, int[] to, int[] cost) {
        int[] cnt = new int[n];
        for (int i : from) cnt[i]++;
        for (int i : to) cnt[i]++;
    
        int[][][] g = new int[n][][];
        for (int i=0; i<n; i++) g[i] = new int[cnt[i]][2];
        for (int i=0; i<from.length; i++) {
            int f = from[i];
            int t = to[i];
            g[f][--cnt[f]][0] = t;
            g[t][--cnt[t]][0] = f;
            g[f][cnt[f]][1] = g[t][cnt[t]][1] = cost[i];
        }
    
        return g;
    }

    public static void main(String[] args) throws Exception {
        long start = System.currentTimeMillis();

        solve();
        out.flush();

        long end = System.currentTimeMillis();
        //trace(end-start + "ms");
        in.close();
    }

    static void trace(Object... o) { System.out.println(deepToString(o));}

    static final byte[] buf = new byte[1024];
    static int ptr = 0;
    static int buflen = 0;

    static boolean hasNextByte() {
        if (ptr < buflen)
            return true;
        ptr = 0;
        try{
            buflen = in.read(buf);
        }catch (IOException e) {e.printStackTrace();}
        if (buflen <= 0)
            return false;
        return true;
    }

    static int readByte() { if (hasNextByte()) return buf[ptr++]; else return -1;}

    static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}

    static void skip() { while(hasNextByte() && !isPrintableChar(buf[ptr])) ptr++;}

    static boolean hasNext() {skip(); return hasNextByte();}

    static String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    static long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        boolean minus = false;
        long num = readByte();

        if(num == '-'){
            num = 0;
            minus = true;
        }else if (num < '0' || '9' < num){
            throw new NumberFormatException();
        }else{
            num -= '0';
        }
        
        while(true){
            int b = readByte();
            if('0' <= b && b <= '9')
                num = num * 10 + (b - '0');
            else if(b == -1 || !isPrintableChar(b))
                return minus ? -num : num;
            else
                throw new NoSuchElementException();
        }
    }

    static int nextInt() {
        long num = nextLong();
        if (num < Integer.MIN_VALUE || Integer.MAX_VALUE < num)
            throw new NumberFormatException();
        return (int)num;
    }

    static double nextDouble() {
        return Double.parseDouble(next());
    }

    static char nextChar() {
        if (!hasNext()) throw new NoSuchElementException();
        return (char)readByte();
    }

    static String nextLine() {
        while (hasNextByte() && (buf[ptr] == '\n' || buf[ptr] == '\r')) ptr++;
        if (!hasNextByte()) throw new NoSuchElementException();

        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (b != '\n' && b != '\r') {
            sb.appendCodePoint(b);
            b = readByte();
        }

        return sb.toString();
    }

    static int[] nextArrayInt(int n) {
        int[] a = new int[n];
        for (int i=0; i<n; i++) a[i] = nextInt();
        return a;
    }
}