#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <random>
#include <iomanip>
#include <functional>
#include <cassert>
using namespace std;
typedef long long ll;
const ll Inf = 1e18;
struct Node {
int val, id;
Node(int val, int id) : val(val), id(id) {}
Node() : val((int)2e9), id(-1) {}
Node operator +(const Node &other) const {
if (val <= other.val) return (*this);
else return other;
}
};
const int N = 2e5 + 7;
Node t[4 * N];
void build(int l, int r, int v, vector <int> &a) {
if (l == r) {
t[v] = Node(a[l], l);
} else {
int m = (l + r) >> 1;
build(l, m, 2 * v + 1, a);
build(m + 1, r, 2 * v + 2, a);
t[v] = t[2 * v + 1] + t[2 * v + 2];
}
}
Node get(int ql, int qr, int l, int r, int v) {
if (qr < l || r < ql) return Node();
if (ql <= l && r <= qr) return t[v];
int m = (l + r) >> 1;
return get(ql, qr, l, m, 2 * v + 1) + get(ql, qr, m + 1, r, 2 * v + 2);
}
void kill(int id, int l, int r, int v) {
if (l == r) {
t[v] = Node();
} else {
int m = (l + r) >> 1;
if (id <= m) kill(id, l, m, 2 * v + 1);
else kill(id, m + 1, r, 2 * v + 2);
t[v] = t[2 * v + 1] + t[2 * v + 2];
}
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
freopen("input.txt", "r", stdin);
#endif
int n, m;
cin >> n >> m;
vector <int> t(m), l(m), r(m), c(m);
vector <pair <int, int>> cm;
for (int i = 0; i < m; ++i) {
cin >> t[i] >> l[i] >> r[i] >> c[i];
--l[i];
cm.push_back({l[i] + t[i], i});
}
sort(cm.begin(), cm.end());
vector <int> a(m);
vector <int> pos(m);
for (int i = 0; i < m; ++i) {
int id = cm[i].second;
a[i] = l[id] - t[id];
pos[id] = i;
}
build(0, m - 1, 0, a);
// r[i] - t[i] >= l[j] - t[j]
// r[i] + t[i] >= l[j] + t[j]
// i -> j
set <pair <ll, int>> q;
for (int i = 0; i < m; ++i) {
if (l[i] == 0) {
q.insert({c[i], i});
kill(pos[i], 0, m - 1, 0);
}
}
ll ans = Inf;
while (!q.empty()) {
auto p = *q.begin();
q.erase(q.begin());
int u = p.second;
ll cd = p.first;
if (r[u] == n) ans = min(ans, cd);
int cr = upper_bound(cm.begin(), cm.end(), make_pair(r[u] + t[u], n)) - cm.begin() - 1;
while (true) {
auto nd = get(0, cr, 0, m - 1, 0);
if (nd.val <= r[u] - t[u]) {
int v = cm[nd.id].second;
kill(pos[v], 0, m - 1, 0);
q.insert({cd + c[v], v});
} else {
break;
}
}
}
if (ans == Inf) cout << "-1\n";
else cout << ans << '\n';
}
