#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <queue>
typedef long long ll;
using namespace std;
const int maxm = 1 << 17;
priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > st[2][maxm * 2];
vector<int> cm[2]; // skomprimovane x suradnice
ll dist[maxm]; // vzdialenosti
int n, m;
void update(int ly, int x, int y, int i)
{
x = lower_bound(cm[ly].begin(), cm[ly].end(), x) - cm[ly].begin();
for (x += maxm; x > 0; x >>= 1)
st[ly][x].push({ y, i });
}
vector<int> v;
void query(int ly, int x, int y)
{
x = lower_bound(cm[ly].begin(), cm[ly].end(), x) - cm[ly].begin();
for (int r = x + maxm + 1; r > 0; r >>= 1) if (r & 1)
{
r--;
while (!st[ly][r].empty() && st[ly][r].top().first <= y)
{
int i = st[ly][r].top().second; st[ly][r].pop();
if (!dist[i]) v.push_back(i);
}
}
}
struct project { int t, l, r, c; } p[maxm];
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m;
priority_queue<pair<ll, int>, vector<pair<ll, int> >, greater<pair<ll, int> > > mini;
for (int i = 0; i < m; i++)
{
cin >> p[i].t >> p[i].l >> p[i].r >> p[i].c, p[i].l--;
if (!p[i].l) mini.push({ p[i].c, i }), dist[i] = p[i].c;
cm[0].push_back(-p[i].t), cm[1].push_back(p[i].t);
}
for (int l = 0; l < 2; l++)
{
sort(cm[l].begin(), cm[l].end());
for (int i = 0; i < m; i++) update(l, (l == 0 ? -p[i].t : p[i].t), (l == 0 ? p[i].l + p[i].t : p[i].l - p[i].t), i);
}
while (!mini.empty())
{
int i = mini.top().second;
mini.pop();
if (p[i].r == n)
{
cout << dist[i] << "\n";
return 0;
}
v.clear();
query(0, -p[i].t, p[i].r + p[i].t);
query(1, p[i].t, p[i].r - p[i].t);
for (int j : v) if (!dist[j])
{
//cout << i << " -> " << j << "\n";
dist[j] = dist[i] + (ll)p[j].c;
mini.push({ dist[j], j });
}
}
cout << "-1\n";
return 0;
}
