#include "bits/stdc++.h"
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> veci;
typedef vector<ll> vecll;
typedef vector<string> vecs;
template<class T,class U> using Hash=unordered_map<T,U>;
 
#define REP(i, a, n) for(ll i = a; i < (ll)(n); i++)
#define RREP(i, a, n) for(ll i = n-1; i >= (ll)(a); i--)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) RREP(i, 0, n)
#define MD 1000000007
#define _SPLIT " "
 
template<class T> T read(){T a;cin >> a;return a;}
template<class T> void read(T& a){cin >> a;}
template<class T,class ...Args> void read(T& a, Args&... args){cin >> a; read(args...);} 
template<class T> void rarr(T a, int n){for(int i = 0; i < n; i++) {cin >> a[i];}}
template<class T> void write(T a){cout << setprecision(12) << a << endl;}
template<class T,class ...Args> void write(T a, Args... args){cout << setprecision(12) << a << _SPLIT; write(args...);}
template<class T> void warr(vector<T> a, const char* c = " "){cout << a[0];for(int i = 1; i < (int)a.size(); i++)cout << c << a[i];cout << endl;;}
template<class T> void warr(T a, int n, const char* c = " "){cout << a[0];for(int i = 1; i < n; i++)cout << c << a[i];cout << endl;}
void split(string s, string delim, veci& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(atoi(s.substr(pos).data()));break;}else {result.push_back(atoi(s.substr(pos, p - pos).data()));}pos = p + delim.size();}}
void split(string s, string delim, vecs& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(s.substr(pos));break;}else {result.push_back(s.substr(pos, p - pos));}pos = p + delim.size();}}
ll gcd(ll a, ll b){while(true){ll k = a % b;if(k == 0)return b;a = b;b = k;}}
ll comb(ll n, ll m){ll p=1;m=min(m,n-m);for(ll i=1;i<=m;i++){p*=n-i+1;p/=i;}return p;}

typedef pair<int,vector<int>> my_pair;

bool operator<(vector<int>& a,vector<int>& b){
    int size=min(a.size(),b.size());
    for(int i=0;i<size;i++){
        if(a[i]<b[i])return true;
        else if(a[i]>b[i])return false;
    }
    return (int)a.size()==size;
}

struct WeightedStaticGraph {
	typedef int Vertex;
	typedef my_pair Weight; typedef my_pair Dist;
	static const Dist InfDist;
	struct To {
		Vertex to; Weight w;
		To() { }
		To(Vertex to_, Weight w_): to(to_), w(w_) { }
	};
	typedef std::pair<Vertex,To> Edge;
	typedef const To *const_iterator;
 
	void init(int n_, const std::vector<Edge> &edges) {
		n = n_; int m = edges.size();
		tos.resize(m+1); offsets.resize(n+1);
		for(int e = 0; e < m; e ++) offsets[edges[e].first] ++;
		for(int v = 1; v <= n_; v ++) offsets[v] += offsets[v-1];
		for(int e = 0; e < m; e ++)
			tos[-- offsets[edges[e].first]] = edges[e].second;
	}
	int numVertices() const { return n; }
 
	inline const_iterator edgesBegin(int v) const { return &tos[offsets[v]]; }
	inline const_iterator edgesEnd(int v) const { return &tos[offsets[v+1]]; }
private:
	int n;
	std::vector<To> tos;
	std::vector<int> offsets;
};
const WeightedStaticGraph::Dist WeightedStaticGraph::InfDist(0x7fffffffffffffffLL,vector<int>({100}));
typedef WeightedStaticGraph Graph;

template<typename Value, typename Compare = std::less<Value>, typename Index = int>
class BinaryHeap {
	Compare cmp;
	vector<Value> a;
	vector<Index> idx, nodeidx;
	int pos;

public:
	BinaryHeap(Compare cmp_ = Compare()): cmp(cmp_) { }
	BinaryHeap(int n, Compare cmp_ = Compare()): cmp(cmp_) { init(n); }

	void init(int n) {
		a.resize(n+1);
		idx.assign(n+1, -1);
		nodeidx.assign(n+1, -1);
		pos = 1;
	}

	const Value &min() const { return a[1]; }
	const Value &get(Index i) const { return a[nodeidx[i]]; }
	Index argmin() const { return idx[1]; }
	Index size() const { return pos - 1; }
	bool empty() const { return pos == 1; }

	const Value &add(Index i, const Value &x) {
		Index node = nodeidx[i];
		if(node >= 0) return a[node];
		a[pos] = x;
		idx[pos] = i;
		nodeidx[i] = pos;
		++ pos;
		up(pos-1);
		return x;
	}

	const Value &update(Index i, const Value &x) {
		Index node = nodeidx[i];
		if(node < 0) {
			a[pos] = x;
			idx[pos] = i;
			nodeidx[i] = pos;
			++ pos;
			up(pos-1);
		}else {
			a[node] = x;
			up(node);
			down(node);
		}
		return x;
	}

	const Value &updatemin(Index i, const Value &x) {
		Index node = nodeidx[i];
		if(node >= 0 && !cmp(x, a[node])) return a[node];
		else return update(i, x);
	}

	const Value remove(Index i) {
		if(i < 0) return Value();
		Index node = nodeidx[i];
		if(node < 0) return Value();
		-- pos;
		idx[node] = idx[pos];
		nodeidx[idx[pos]] = node;
		nodeidx[i] = -1;
		idx[pos] = -1;
		swap(a[pos], a[node]);
		up(node);
		down(node);
		return a[pos];
	}

private:
	void up(Index i) {
		for(Index c = i, p = c >> 1; p > 0 && cmp(a[c], a[p]); c >>= 1, p >>= 1) {
			swap(a[p], a[c]);
			swap(nodeidx[idx[p]], nodeidx[idx[c]]);
			swap(idx[p], idx[c]);
		}
	}

	void down(Index i) {
		Index bottom = pos;
		for(Index c = i; c * 2 < bottom; ) {
			Index b = c * 2 + (c * 2 + 1 < bottom && cmp(a[c * 2 + 1], a[c * 2]));
			if(!cmp(a[b], a[c])) break;
			swap(a[c], a[b]);
			swap(nodeidx[idx[c]], nodeidx[idx[b]]);
			swap(idx[c], idx[b]);
			c = b;
		}
	}
};


void dijkstra(const Graph &g, int s, vector<Graph::Dist> &dist) {
	int n = g.numVertices();
	dist.assign(n, Graph::InfDist);
	vector<bool> vis(n);
	BinaryHeap<Graph::Dist> h(n);
	h.add(s, my_pair(0,vector<int>({s})));
	while(!h.empty()) {
		int v = h.argmin();
		dist[v] = h.get(v);
		h.remove(v);
		vis[v] = true;
		for(Graph::const_iterator it = g.edgesBegin(v), et = g.edgesEnd(v); it != et; ++ it) {
			if(!vis[it->to]){
                vector<int> t=dist[v].second;
                t.push_back(it->to);
				h.updatemin(it->to, my_pair(dist[v].first + it->w.first,t));
            }
		}
	}
}

int main(void)
{
    int n,m,s,g;
    vector<Graph::Edge> e;
    Graph gr;
    read(n,m,s,g);
    rep(i,m){
        Graph::Edge p;
        read(p.first,p.second.to,p.second.w.first);
        e.push_back(p);
        swap(p.first,p.second.to);
        e.push_back(p);
    }
    gr.init(n,e);
    vector<Graph::Dist> dist;
    dijkstra(gr, s, dist);
    warr(dist[g].second);
    return 0;
}