/* -*- coding: utf-8 -*-
 *
 * 614.cc: No.614 壊れたキャンパス - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 200000;
const int MAX_M = 200000;

typedef long long ll;
const ll LINF = 1LL << 60;

/* typedef */

typedef pair<int,int> pii;
typedef vector<pii> vpii;

/* global variables */

vpii nbrs[MAX_N];
ll dp[2][MAX_M];

/* subroutines */

inline ll absll(ll a) { return (a >= 0) ? a : -a; }
inline void setmin(ll &a, ll b) { if (a > b) a = b; }

/* main */

int main() {
  int n, m, k, st, gl;
  scanf("%d%d%d%d%d", &n, &m, &k, &st, &gl);

  for (int i = 0; i < m; i++) {
    int ai, bi, ci;
    scanf("%d%d%d", &ai, &bi, &ci);
    nbrs[ai].push_back(pii(bi, ci));
  }

  nbrs[0].push_back(pii(0, st));
  dp[0][0] = 0;
  int cur = 0, nxt = 1;

  for (int i = 1; i < n; i++) {
    vpii &nbr0 = nbrs[i - 1], &nbr1 = nbrs[i];
    if (nbr1.empty()) {
      puts("-1");
      return 0;
    }

    int n0 = nbr0.size(), n1 = nbr1.size();
    fill(dp[nxt], dp[nxt] + n1, LINF);

    for (int j0 = 0; j0 < n0; j0++) {
      int &f0 = nbr0[j0].second;
      for (int j1 = 0; j1 < n1; j1++)
	setmin(dp[nxt][j1], dp[cur][j0] + absll(nbr1[j1].first - f0));
    }

    cur ^= 1, nxt ^= 1;
  }

  ll mind = LINF;
  for (int j = 0; j < nbrs[n - 1].size(); j++)
    setmin(mind, dp[cur][j] + absll(gl - nbrs[n - 1][j].second));
  printf("%lld\n", mind);
  return 0;
}