#include <bits/stdc++.h>

using namespace std;
using ll = long long;

struct Segment {
    int t, l, r, w;
};

constexpr ll inf = 3e18;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    vector<Segment> s(m);

    for (auto &[t, l, r, w] : s) {
        cin >> t >> l >> r >> w;
    }

    sort(s.begin(), s.end(), [&](const auto &x, const auto &y) {
        return array{x.r - x.t, y.l} < array{y.r - y.t, y.l};
    });

    vector<ll> dp(m, inf);
    vector<bool> used(m);

    for (int i = 0; i < m; ++i) {
        if (s[i].l == 1) {
            dp[i] = s[i].w;
        }
    }

    for (int _ = 0; _ < m; ++_) {
        int v = -1;
        for (int i = 0; i < m; ++i) {
            if (!used[i] && (v == -1 || dp[v] > dp[i])) {
                v = i;
            }
        }
        dp[v] += s[v].w;
        used[v] = true;
        for (int to = 0; to < m; ++to) {
            if (!used[to] && s[v].r - s[to].l + 1 >= abs(s[v].t - s[to].t)) {
                dp[to] = min(dp[to], dp[v]);
            }
        }
    }

    ll ans = inf;

    for (int i = 0; i < m; ++i) {
        if (s[i].r == n) {
            ans = min(ans, dp[i]);
        }
    }

    if (ans == inf) {
        cout << "-1\n";
    } else {
        cout << ans << '\n';
    }

    return 0;
}