#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll inf = 1e16;
array <ll, 4> a[5001];
int n, m;
vector <int> adj[5001];
ll dist[5001];
void solve () {
cin >> n >> m;
for (int i = 1; i <= m; i++) {
for (int j = 0; j < 4; j++) {
cin >> a[i][j];
}
a[i][1]--;
}
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= m; j++) {
if (a[i][0] <= a[j][0]) {
if (a[j][1] <= a[i][2] - (a[j][0] - a[i][0])) {
adj[i].push_back(j);
}
}
if (a[i][0] >= a[j][0]) {
if (a[i][2] >= a[j][1] + (a[i][0] - a[j][0])) {
adj[i].push_back(j);
}
}
}
}
for (int i = 1; i <= m; i++) {
dist[i] = inf;
}
priority_queue <pair <ll, ll>, vector <pair <ll, ll>>, greater <>> pq;
for (int i = 1; i <= m; i++) {
if (a[i][1] == 0) {
pq.push({0, i});
dist[i] = 0;
}
}
while (!pq.empty()) {
auto k = pq.top();
pq.pop();
if (k.first > dist[k.second]) {
continue;
}
for (auto j : adj[k.second]) {
if (dist[j] > k.first + a[k.second][3]) {
dist[j] = k.first + a[k.second][3];
pq.push({dist[j], j});
}
}
}
ll mn = inf;
for (int i = 1; i <= m; i++) {
if (a[i][2] == n) {
mn = min(mn, dist[i] + a[i][3]);
}
}
if (mn == inf) {
cout << -1 << '\n';
} else {
cout << mn << '\n';
}
}
signed main () {
ios::sync_with_stdio(0); cin.tie(0);
int tc = 1; //cin >> tc;
while (tc--) solve();
}
