#include <iostream>
#include <set>
#include <unordered_map>
#include <vector>
#include <utility>

using namespace std;
long E[5000][5000];
unordered_map <long, set<int>> G;

#define pairs pair<int, int>

int main() {
    int n, m;
    cin>>n>>m;
    int s, f;
    cin>>s>>f;
    int a, b, c;
    for (int i = 0; i < m; i++) {
        cin>>a>>b>>c;
        E[a-1][b-1] = c;
        E[b-1][a-1] = c;
        G[a-1].emplace(b-1);
        G[b-1].emplace(a-1);

    }

    if(s == f) {
        cout<<0;
        return 0;
    }

    long d[1000];
    set<int> used;
    set<pairs> A;
    int parent[1000];
    for (int i = 0; i < n; i++) {
        d[i] = 100000*5000+4;
        parent[n] = 0;
        A.insert(make_pair(100000*5000+4, i));
        parent[i] = -1;
    }
    A.insert(make_pair(0, s-1));
    bool found = false;
    auto x = A.begin();
    while(!found) {
        auto x = A.begin();
        if(x->first == 100000*5000+4) found = true;
        A.erase(x);
        if(used.find(x->second) != used.end()) continue;
        used.insert(x->second);
        if(x->second == f-1) found = true;
        for(auto v:G[x->second]) {
            if(used.find(v) == used.end()) {
                if (E[x->second][v] + x->first < d[v]) {
                    d[v] = E[x->second][v] + x->first;
                    parent[v] = x->second;
                    A.insert(make_pair(d[v], v));
                }
            }
        }
    }
    vector<int> p;
    int l = f-1;
    p.push_back(l);
    if(d[f-1] == 100000*5000+4) cout<<-1;

    else{
        while(true) {
            l = parent[l];
            p.push_back(l);
            if(l == s-1) break;
        }
        cout<<d[f-1]<<"\n";
        for(int i = p.size() - 1; i >=0 ; i--) {
            cout<<p[i]+1<<" ";
        }
    }


    return 0;
}
/*
 * 5 7
1 5
1 2 10
1 5 100
2 3 50
3 5 10
3 4 20
4 5 60
1 4 30
 */