#include <iostream>
#include <algorithm>
#include <map>
#include <queue>
#include <vector>
using namespace std;
using i64 = long long;

constexpr i64 inf = 987654321987654321LL;
struct edge { int to, cost; };
int N, M, K, S, T;
vector<tuple<int, int, int>> ABC;

// x棟が開始する番号を返す
int myfind(int x) {
  if(x >= N-1) { return M; }
  int lo = -1, hi = M-1;
  while(hi - lo > 1) {
    int md = (lo + hi) / 2;
    int cand = get<0>(ABC[md]);
    if(x <= cand) {
      hi = md;
    } else {
      lo = md;
    }
  }
  return hi;
}

int main(void) {
  scanf("%d%d%d%d%d", &N, &M, &K, &S, &T);
  --S, --T;
  // G[i] := { (i棟の始点の階, i+1棟の終点の階)のリスト }
  vector<vector<pair<int, int>>> G(N);
//  vector<pair<int, int>> corr0(M), corr1(M); // corr0[i] := 渡り廊下始点の (棟, 階)
//                                             // corr1[i] := 渡り廊下終点の (棟, 階)
  vector<map<int, int>> corr0_rev(N);
  for(int i=0; i<M; ++i) {
    int a, b, c; scanf("%d%d%d", &a, &b, &c);
    --a, --b, --c;
    ABC.emplace_back(a, b, c);
    G[a].emplace_back(b, c);
    corr0_rev[a]  [b] = i;
  }
  sort(begin(ABC), end(ABC));
  vector<vector<edge>> H(M+2);
  for(int a=0; a<N-1; ++a) {
    int a0pos = myfind(a),
        a1pos = myfind(a+1),
        a2pos = myfind(a+2);
    if(a0pos == -1) { continue; }
    for(int p0=a0pos; p0<a1pos; ++p0) {
      int _, b, c; tie(_, b, c) = ABC[p0];
      int node0 = corr0_rev[a][b];
      for(int p1=a1pos; p1<a2pos; ++p1) {
        int _, x, y; tie(_, x, y) = ABC[p1];
        int node1 = corr0_rev[a+1][x];
        H[node0].push_back(edge{node1, abs(c - x)});
      }
    }
  }
  for(auto pr1 : G[0]) {
    int p, q; tie(p, q) = pr1; // 0棟 p階 -> 1棟 q階への渡り廊下
    int node1 = corr0_rev[0][p];
    H[M].push_back(edge{node1, abs(S - p)});
  }
  for(auto pr0 : G[N-2]) {
    int b, c; tie(b, c) = pr0; // N-2棟 b階 -> N-1棟 c階への渡り廊下
    int node0 = corr0_rev[N-2][b];
    H[node0].push_back(edge{M+1, abs(c - T)});
  }

  // コーナーケース
  if(N == 1) {
    H[M].push_back(edge{M+1, abs(S - T)});
  }

  vector<i64> cost(M+2, inf); // cost[M+2]
  cost[M] = 0;
  priority_queue<pair<i64, int>, vector<pair<i64, int>>, greater<pair<i64, int>>> pq;
  vector<bool> seen(M+2, false); // seen[M+2]
  // コスト、点番号
  pq.emplace(0, M);
  while(!pq.empty()) {
    i64 _, v; tie(_, v) = pq.top(); pq.pop();
    if(seen[v]) { continue; }
    seen[v] = true;
    for(edge e : H[v]) {
      if(cost[e.to] > cost[v] + e.cost) {
        cost[e.to] = cost[v] + e.cost;
        pq.emplace(cost[e.to], e.to);
      }
    }
  }
  i64 res = cost[M+1];
  if(res == inf) { res = -1; }
  printf("%lld\n", res);
  return 0;
}