//Challenge: Accepted
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
while (l != r) cout << *l << " ", l++;
cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 100005
#define pii pair<ll, ll>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
const ll inf = 1LL<<60;
vector<pii> lef[maxn];
struct segtree{
vector<pii> seg[4*maxn];
void init(int cur, int l, int r) {
if (r <= l) return;
if (r - l == 1) {
seg[cur] = lef[l];
return;
}
int m = (l + r) / 2;
init(cur*2, l, m), init(cur*2+1, m, r);
int ind = 0;
for (int i = 0;i < seg[cur*2].size();i++) {
while (ind < seg[cur*2+1].size() && seg[cur*2+1][ind] > seg[cur*2][i]) {
seg[cur].push_back(seg[cur*2+1][ind++]);
}
seg[cur].push_back(seg[cur*2][i]);
}
while (ind < seg[cur*2+1].size()) {
seg[cur].push_back(seg[cur*2+1][ind++]);
}
}
void getind(int cur, int l, int r, int ql, int qr, int y, vector<int> &ret, bool add) {
if (r <= l || ql >= r || qr <= l || seg[cur].size() == 0 || seg[cur].back().ff > y) return;
if (ql <= l && qr >= r) {
while (seg[cur].size() && seg[cur].back().ff <= y) {
if (add) ret.push_back(seg[cur].back().ss);
seg[cur].pop_back();
}
add = 0;
}
if (r - l == 1) return;
int m = (l + r) / 2;
getind(cur*2, l, m, ql, qr, y, ret, add);
getind(cur*2+1, m, r, ql, qr, y, ret, add);
}
} tr;
struct seg{
int t, l, r, x, y;
int cost;
seg(){t = l = r = cost = 0;}
} a[maxn];
ll dis[maxn];
int main() {
io
int L, n;
cin >> L >> n;
vector<int> vx;
for (int i = 1;i <= n;i++) {
cin >> a[i].t >> a[i].l >> a[i].r >> a[i].cost;
a[i].x = a[i].l - a[i].t;
a[i].y = a[i].l + a[i].t;
vx.push_back(a[i].x);
}
sort(vx.begin(), vx.end());
vx.resize(int(unique(vx.begin(), vx.end()) - vx.begin()));
for (int i = 1;i <= n;i++) {
a[i].x = lower_bound(vx.begin(), vx.end(), a[i].x) - vx.begin();
lef[a[i].x].push_back({a[i].y, i});
}
for (int i = 0;i < n;i++) sort(lef[i].begin(), lef[i].end());
tr.init(1, 0, n);
priority_queue<pii, vector<pii>, greater<pii> > pq;
for (int i = 1;i <= n;i++) {
dis[i] = inf;
if (a[i].l == 1) {
dis[i] = a[i].cost;
pq.push({dis[i], i});
}
}
dis[n+1] = inf;
while (pq.size()) {
auto [d, cur] = pq.top();
pq.pop();
if (d != dis[cur]) continue;
if (a[cur].r == L) dis[n+1] = min(dis[n+1], d);
vector<int> upd;
int xv = upper_bound(vx.begin(), vx.end(), a[cur].r - a[cur].t + 1) - vx.begin();
tr.getind(1, 0, n, 0, xv, a[cur].r + a[cur].t + 1, upd, 1);
for (int i:upd) {
if (d + a[i].cost < dis[i]) {
dis[i] = d + a[i].cost;
pq.push({dis[i], i});
}
}
}
cout << (dis[n+1] == inf ? -1 : dis[n+1]) << "\n";
}
