#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f first
#define s second
#define pb push_back
#define ep emplace
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define mem(f,x) memset(f , x , sizeof(f))
#define sz(x) (ll)(x).size()
#define __lcm(a, b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define mxx *max_element
#define mnn *min_element
#define cntbit(x) __builtin_popcountll(x)
#define len(x) (int)(x.length())
const int N = 1e6 + 10;
int pos[N];
int T[N], L[N], R[N], C[N], vis[N], rnk[N];
priority_queue <pair <ll, ll>> f[2][N];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m;
cin >> m >> n;
priority_queue <pair <ll, ll>, vector <pair <ll, ll>>, greater <pair <ll, ll>>> pq;
for (int i = 1; i <= n; i++) {
cin >> T[i] >> L[i] >> R[i] >> C[i];
pos[i] = T[i];
if (L[i] == 1) {
pq.push({C[i], i});
vis[i] = 1;
}
}
sort(pos + 1, pos + n + 1);
for (int i = 1; i <= n; i++) {
int p = lower_bound(pos + 1, pos + 1 + n, T[i]) - pos;
rnk[i] = p;
for (int k = p; k; k -= k & (-k))
f[0][k].push({-L[i] - T[i] + 1, i});
for (int k = p; k <= n; k += k & (-k))
f[1][k].push({T[i] - L[i] + 1, i});
}
while (sz(pq)) {
auto tt = pq.top();
pq.pop();
int id = tt.s;
int ra = rnk[id];
if (R[id] == m) {
cout << tt.f << '\n';
return 0;
}
for (int i = ra; i <= n; i += i & (-i)) {
while (sz(f[0][i])) {
auto t = f[0][i].top();
if (vis[t.s]) {
f[0][i].pop();
continue;
}
if (t.f >= -T[id] - R[id]) {
f[0][i].pop();
pq.push({tt.f + C[t.s], t.s});
vis[t.s] = 1;
} else {
break;
}
}
}
for (int i = ra; i; i -= i & (-i)) {
while (sz(f[1][i])) {
auto t = f[1][i].top();
if (vis[t.s]) {
f[1][i].pop();
continue;
}
if (t.f >= T[id] - R[id]) {
f[1][i].pop();
pq.push({tt.f + C[t.s], t.s});
vis[t.s] = 1;
} else {
break;
}
}
}
}
cout << -1 << "\n";
return 0;
}
// case 1:
// t[i] > t[j]
// t[i] - t[j] <= r[i] - l[j] + 1
// t[i] - r[i] <= t[j] - l[j] + 1
// case 2:
// t[i] < t[j]
// t[j] - t[i] <= r[i] - l[j] + 1
// -t[i] - r[i] <= -l[j] - t[j] + 1
