#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using VI = vector<int>;
using VL = vector<ll>;
using VVI = vector<vector<int>>;
using VVL = vector<vector<ll>>;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep2(i, s, n) for (int i = (s); i < (int)(n); i++)
#define rep3(i, s, n, d) for (int i = (s); i < (int)(n); i += (d))
#define allpt(v) (v).begin(), (v).end()
#define allpt_c(v) (v).cbegin(), (v).cend()
#define allpt_r(v) (v).rbegin(), (v).rend()

const int mod = 1e9 + 7, mod2 = 998244353;
const ll inf = 1e18;

const string wsp = " ";
const string tb = "\t";
const string rt = "\n";

template <typename T>
void show1dvec(const vector<T> &v)
{
    if (v.size() == 0)
        return;
    int n = v.size() - 1;
    rep(i, n) cout << v[i] << wsp;
    cout << v[n] << rt;
    ;
    return;
}

template <typename T>
void show2dvec(const vector<vector<T>> &v)
{
    int n = v.size();
    rep(i, n) show1dvec(v[i]);
}

template <typename T, typename S>
void show1dpair(const vector<pair<T, S>> &v)
{
    int n = v.size();
    rep(i, n) cout << v[i].first << wsp << v[i].second << rt;
    return;
}

template <typename T, typename S>
void pairzip(const vector<pair<T, S>> &v, vector<T> &t, vector<T> &s)
{
    int n = v.size();
    rep(i, n)
    {
        t.push_back(v[i].first);
        s.push_back(v[i].second);
    }
    return;
}

template <typename T>
void maxvec(vector<T> &v)
{
    T s = v[0];
    int n = v.size();
    rep(i, n - 1)
    {
        if (s > v[i + 1])
        {
            v[i + 1] = s;
        }
        s = v[i + 1];
    }
}

template <typename T, typename S>
bool myfind(T t, S s)
{
    return find(t.cbegin(), t.cend(), s) != t.cend();
}

bool check(int y, int x, int h, int w)
{
    return 0 <= y && y < h && 0 <= x && x < w;
}

VL cumsum(const VL &v)
{
    int s = 0;
    VL ret = {0};

    rep(i, v.size())
    {
        s += v[i];
        ret.push_back(s);
    }
    return ret;
}

bool iskadomatsu(int a, int b, int c)
{
    return (a != b && b != c && c != a) && ((a > b && b < c) || (a < b && b > c));
}

void djkstra(int x, VI &beforepoint, VI &shortest, vector<vector<PII>> &connect)
{
    vector<int> search = {x};
    vector<int> new_search;
    shortest[x] = 0;
    int v, d;
    while (!search.empty())
    {
        for (auto i : search)
        {
            for (auto j : connect[i])
            {
                v = j.first, d = j.second;
                if (shortest[v] > d + shortest[i])
                {
                    shortest[v] = d + shortest[i];
                    beforepoint[v] = i;
                    new_search.push_back(v);
                }
                else if (shortest[v] == d + shortest[i] && beforepoint[v] > i)
                    beforepoint[v] = i;
            }
        }
        search.clear();
        search = new_search;
        new_search.clear();
    }
}



int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    int n, m, s, g, a, b, c, q;
    cin >> n >> m >> s >> g;
    VI beforepoint(n, n), shortest(n, 1e9), ans{g};
    vector<vector<PII>> connect(n);
    
    rep(i, m)
    {
        cin >> a >> b >> c;
        connect[a].push_back(make_pair(b, c));
        connect[b].push_back(make_pair(a, c));
    }

    djkstra(s, beforepoint, shortest, connect);

    q = g;
    while(beforepoint[q] != n)
    {
        ans.push_back(beforepoint[q]);
        q = beforepoint[q];
    }
    reverse(allpt(ans));
    show1dvec(ans);
    
    return 0;
}