#include <bits/stdc++.h>
#define se second
#define fs first
#define mp make_pair
#define pb push_back
#define ll long long
#define ii pair<ll,ll>
#define ld long double
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(), v.end()
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now().time_since_epoch().count());
ll Rand(ll l, ll r)
{
return uniform_int_distribution<ll> (l, r)(rd);
}
const int N = 2e5 + 7;
const int Mod =1e9 + 7;
const int szBL = 916;
const ll INF = 1e18;
const int BASE = 137;
struct Data {
ll T, L, R, C;
};
int n, m;
Data a[N];
vector<pair<ll,ll>> ke[N];
ll Dist[N];
void solution () {
cin >> n >> m;
rep (i, 1, m) {
cin >> a[i].T >> a[i].L >> a[i].R >> a[i].C;
--a[i].L;
}
rep (i, 1, m)
rep (j, 1, m) {
if (i == j) continue;
if (a[i].T <= a[j].T) {
if (a[i].R + a[i].T >= a[j].L + a[j].T) ke[i].push_back({j, a[j].C});
}
else {
if (a[i].R - a[i].T >= a[j].L - a[j].T) ke[i].push_back({j, a[j].C});
}
}
memset(Dist, 0x3f, sizeof Dist);
priority_queue<pair<ll,ll>, vector<pair<ll,ll>>, greater<pair<ll,ll>>> pq;
rep (i, 1, m) {
if (a[i].L == 0) {
pq.push({a[i].C, i});
Dist[i] = a[i].C;
}
}
while (!pq.empty()) {
int u = pq.top().se;
if (a[u].R == n) {
cout << Dist[u] <<"\n";
return;
}
pq.pop();
iter (&id, ke[u]) {
ll v, w;
tie (v, w) = id;
if (Dist[v] > Dist[u] + w) {
Dist[v] = Dist[u] + w;
pq.push({Dist[v], v});
}
}
}
cout << -1 <<"\n";
}
#define file(name) freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);
int main () {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
// file ("c");
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
1 2
*/
