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// 더 많은 알고리즘/풀이 글은 42jerrykim.github.io에서 확인하세요.
#include <bits/stdc++.h>
using namespace std;

using int64 = long long;
const int64 INF = (1LL<<62);

struct Project {
    int64 T, L, R, C; // L is shifted later (L-1)
    int tpos;         // compressed T index
    int64 valF;       // L + T
    int64 valB;       // L - T
    int64 thF;        // R + T
    int64 thB;        // R - T
};

struct SegMin {
    int n; vector<int64> tree;
    SegMin() {}
    SegMin(int sz, const vector<int64>& init) { build(sz, init); }
    void build(int sz, const vector<int64>& init) {
        n = 1; while (n < sz) n <<= 1;
        tree.assign(2*n, INF);
        for (int i = 0; i < (int)init.size(); ++i) tree[n+i] = init[i];
        for (int i = n-1; i >= 1; --i) tree[i] = min(tree[i<<1], tree[i<<1|1]);
    }
    void point_set(int pos, int64 val) {
        int p = pos + n; tree[p] = val;
        for (p >>= 1; p; p >>= 1) tree[p] = min(tree[p<<1], tree[p<<1|1]);
    }
    int find_first_le(int l, int r, int64 limit) { return find_first_le_impl(1, 0, n-1, l, r, limit); }
    int find_first_le_impl(int node, int nl, int nr, int ql, int qr, int64 limit) {
        if (qr < nl || nr < ql) return -1;
        if (tree[node] > limit) return -1;
        if (nl == nr) return nl;
        int mid = (nl + nr) >> 1;
        int left = find_first_le_impl(node<<1, nl, mid, ql, qr, limit);
        if (left != -1) return left;
        return find_first_le_impl(node<<1|1, mid+1, nr, ql, qr, limit);
    }
};

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

    int64 N; int M;
    if (!(cin >> N >> M)) return 0;

    vector<Project> a(M);
    vector<int64> allT; allT.reserve(M);
    for (int i = 0; i < M; ++i) {
        cin >> a[i].T >> a[i].L >> a[i].R >> a[i].C;
        a[i].L -= 1; // make half-open
        allT.push_back(a[i].T);
    }

    sort(allT.begin(), allT.end());
    allT.erase(unique(allT.begin(), allT.end()), allT.end());
    for (int i = 0; i < M; ++i) {
        a[i].tpos = int(lower_bound(allT.begin(), allT.end(), a[i].T) - allT.begin());
        a[i].valF = a[i].L + a[i].T;
        a[i].valB = a[i].L - a[i].T;
        a[i].thF = a[i].R + a[i].T;
        a[i].thB = a[i].R - a[i].T;
    }

    int Tcnt = (int)allT.size();
    vector<vector<int>> grpF(Tcnt), grpB(Tcnt);
    vector<int> ptrF(Tcnt, 0), ptrB(Tcnt, 0);

    vector<int> seeds, exitNodes;
    seeds.reserve(M); exitNodes.reserve(M);
    for (int i = 0; i < M; ++i) {
        if (a[i].L == 0) seeds.push_back(i);
        else {
            grpF[a[i].tpos].push_back(i);
            grpB[a[i].tpos].push_back(i);
        }
        if (a[i].R == N) exitNodes.push_back(i);
    }

    if (seeds.empty() || exitNodes.empty()) {
        cout << -1 << '\n';
        return 0;
    }

    for (int t = 0; t < Tcnt; ++t) {
        sort(grpF[t].begin(), grpF[t].end(), [&](int i, int j){ return a[i].valF < a[j].valF; });
        sort(grpB[t].begin(), grpB[t].end(), [&](int i, int j){ return a[i].valB < a[j].valB; });
    }

    vector<int64> headF(Tcnt, INF), headB(Tcnt, INF);
    for (int t = 0; t < Tcnt; ++t) {
        if (!grpF[t].empty()) headF[t] = a[grpF[t][0]].valF;
        if (!grpB[t].empty()) headB[t] = a[grpB[t][0]].valB;
    }
    SegMin segF(Tcnt, headF), segB(Tcnt, headB);

    vector<int64> dist(M, INF);
    priority_queue<pair<int64,int>, vector<pair<int64,int>>, greater<pair<int64,int>>> pq;
    for (int i : seeds) { dist[i] = a[i].C; pq.push({dist[i], i}); }

    while (!pq.empty()) {
        auto [d, i] = pq.top(); pq.pop();
        if (d != dist[i]) continue;

        int tpos = a[i].tpos;

        // T_j >= T_i, activate by valF <= thF
        {
            int64 limit = a[i].thF;
            while (true) {
                int pos = segF.find_first_le(tpos, Tcnt-1, limit);
                if (pos == -1) break;
                int j = grpF[pos][ptrF[pos]++];
                int64 newHead = (ptrF[pos] < (int)grpF[pos].size()) ? a[grpF[pos][ptrF[pos]]].valF : INF;
                segF.point_set(pos, newHead);
                int64 nd = d + a[j].C;
                if (nd < dist[j]) { dist[j] = nd; pq.push({nd, j}); }
            }
        }

        // T_j <= T_i, activate by valB <= thB
        {
            int64 limit = a[i].thB;
            while (true) {
                int pos = segB.find_first_le(0, tpos, limit);
                if (pos == -1) break;
                int j = grpB[pos][ptrB[pos]++];
                int64 newHead = (ptrB[pos] < (int)grpB[pos].size()) ? a[grpB[pos][ptrB[pos]]].valB : INF;
                segB.point_set(pos, newHead);
                int64 nd = d + a[j].C;
                if (nd < dist[j]) { dist[j] = nd; pq.push({nd, j}); }
            }
        }
    }

    int64 ans = INF;
    for (int j : exitNodes) ans = min(ans, dist[j]);
    cout << (ans >= INF/2 ? -1 : ans) << '\n';
    return 0;
}