#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

typedef tuple<int, string, int> P;

vector<pii> g[200];

int main(){
    int N, M, S, G;
    cin >> N >> M >> S >> G;

    rep(i, M){
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }

    priority_queue<P,vector<P>,greater<P>> Q;
    Q.push(P(0, string(1, (char)S), S));
    vi vis(N);
    while(sz(Q)){
        string s;
        int d, u;
        tie(d, s, u) = Q.top();
        Q.pop();
        if(vis[u]++)continue;
        if(u == G){
            rep(i, sz(s))printf("%d%c", (int)s[i], i != sz(s) - 1 ? ' ' : '\n');
            return 0;
        }
        each(e, g[u]){
            int v, c;
            tie(v, c) = e;
            if(!vis[v]){
                Q.push(P(d + c, s + (char)v, v));
            }
        }
    }
}