#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
#define int long long
#define fi first
#define se second
#define L(i, j, k) for (int i = (j); i <= (k); i++)
#define R(i, j, k) for (int i = (j); i >= (k); i--)
#define all(x) x.begin(), x.end()
const int N = 3005;
const int inf = 1e18;
struct Treatment {
int t, l, r, c;
} arr[N];
int di[N];
vector<pair<int, int>> adj[2 * N];
void ae(int u, int v, int w) {
// cout << "addedge: " << u << " " << v << " " << w << '\n';
adj[u].push_back({v, w});
}
void solve() {
int n, m;
cin >> n >> m;
for (int i = 1; i <= m; i++) cin >> arr[i].t >> arr[i].l >> arr[i].r >> arr[i].c;
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= m; j++) {
if (i == j) continue;
int td = abs(arr[i].t - arr[j].t);
if (arr[j].l <= arr[i].r + 1 - td) ae(i, j, arr[j].c);
}
if (arr[i].l == 1) ae(0, i, arr[i].c);
}
di[0] = 0;
for (int i = 1; i <= m; i++) di[i] = inf;
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<>> q;
q.push({0, 0});
while (!q.empty()) {
auto [d, u] = q.top();
q.pop();
if (d != di[u]) continue;
for (auto& [v, w] : adj[u]) {
if (di[v] > di[u] + w) {
di[v] = di[u] + w;
q.push({di[v], v});
}
}
}
int ans = inf;
for (int i = 1; i <= m; i++) if (arr[i].r == n) ans = min(ans, di[i]);
if (ans == inf) cout << "-1\n";
else cout << ans << '\n';
// sort projects, then point to interval edges
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int test = 1;
// cin >> test;
while (test--) solve();
}
