#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;

struct P {
    bool operator<(const P& p) const {
        return a < p.a;
    }
    int a, b, c;
    int64_t d;
};

struct Q {
    bool operator<(const Q& q) const {
        return c < q.c;
    }
    int c, i;
    int64_t d;
};

int main() {
    int n, m, k, s, t;
    cin >> n >> m >> k >> s >> t;

    vector<P> p(m + 2);
    p[0] = { 0, 0, s, 0 };
    p[m + 1] = { n, t, 0, 0 };
    for (int i = 1; i <= m; i++) {
        cin >> p[i].a >> p[i].b >> p[i].c;
    }

    sort(p.begin(), p.end());

    vector<int> l(n + 2);
    for (int i = m + 1; i >= 0; i--) {
        l[p[i].a] = i;
    }
    l[n + 1] = m + 2;

    for (int i = 1; i < n; i++) {
        if (l[i] == 0) {
            cout << -1 << endl;
            quick_exit(0);
        }
    }

    vector<Q> q(m + 2);
    for (int a = 0; a < n; a++) {
        int h = 0;
        for (int i = l[a]; i < l[a + 1]; i++) {
            q[h++] = { p[i].c, -1, p[i].d };
        }
        for (int i = l[a + 1]; i < l[a + 2]; i++) {
            q[h++] = { p[i].b, i, -1 };
        }
        sort(q.begin(), q.begin() + (l[a + 2] - l[a]));

        int64_t d = (int64_t)1 << 60;
        for (int i = 0; i < h; i++) {
            if (i != 0) d += q[i].c - q[i - 1].c;
            if (q[i].i < 0) {
                d = min(d, q[i].d);
            } else {
                if (q[i].d < 0 || q[i].d > d) q[i].d = d;
            }
        }
        d = (int64_t)1 << 60;
        for (int i = h - 1; i >= 0; i--) {
            if (i != h - 1) d += q[i + 1].c - q[i].c;
            if (q[i].i < 0) {
                d = min(d, q[i].d);
            } else {
                if (q[i].d < 0 || q[i].d > d) q[i].d = d;
            }
        }

        for (int i = 0; i < h; i++) {
            if (q[i].i >= 0) {
                p[q[i].i].d = q[i].d;
            }
        }
    }

    cout << p[m + 1].d << endl;

    return 0;
}