#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

typedef pair<int, int> P;
typedef tuple<ll, int, int> State; // dist, building, floor
const ll INF = 1LL << 60;
map<P, int> vmap;
map<P, vector<int>> nxt; // building floor-> next floor
vector<int> F[200000];
ll dist[500000];

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
#ifdef LOCAL
	std::ifstream in("in");
	std::cin.rdbuf(in.rdbuf());
#endif

	int N, M, K, S, T;
	cin >> N >> M >> K >> S >> T;
	F[0].push_back(S);
	F[N - 1].push_back(T);
	for(int i = 0; i < M; i++){
		int a, b, c;
		cin >> a >> b >> c;
		a--;
		F[a].push_back(b);
		F[a + 1].push_back(c);
		nxt[{a, b}].push_back(c);
	}

	int V = 0;
	for(int i = 0; i < N; i++){
		sort(F[i].begin(), F[i].end());
		F[i].erase(unique(F[i].begin(), F[i].end()), F[i].end());
		for(auto f : F[i]){
			vmap[{i, f}] = V++;
		}
	}
	P start = { 0, S };
	P goal = { N - 1, T };
	if(vmap.count(start) == 0) vmap[start] = V++;
	if(vmap.count(goal) == 0) vmap[goal] = V++;

	fill((ll*)begin(dist), (ll*)end(dist), INF);
	dist[vmap[start]] = 0;
	priority_queue<State, vector<State>, greater<State>> q;
	q.push({ 0, 0, S });
	while(q.size()){
		ll d;
		int b, f;
		tie(d, b, f) = q.top();
		q.pop();
		if(nxt.count({ b, f })){
			for(auto nc : nxt[{b, f}]){
				State ns = { d, b + 1, nc };
				if(dist[vmap[{ b + 1, nc }]] > d){
					dist[vmap[{ b + 1, nc }]] = d;
					q.push(ns);
				}
			}
		}
		int idx = lower_bound(F[b].begin(), F[b].end(), f) - F[b].begin();
		for(int i = idx - 1; i <= idx + 1; i += 2){
			if(i < 0 || F[b].size() <= i) continue;
			ll nd = d + abs(f - F[b][i]);
			State ns = { nd, b, F[b][i] };
			if(dist[vmap[{ b, F[b][i] }]] > nd){
				dist[vmap[{ b, F[b][i] }]] = nd;
				q.push(ns);
			}
		}
	}

	if(dist[vmap[goal]] == INF) cout << -1 << endl;
	else cout << dist[vmap[goal]] << endl;
}