#include<bits/stdc++.h>
#define ll long long
#define pll pair<ll, ll>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ld long double
#define sz(a) ((ll)(a).size())
using namespace std;
const ll maxn=100005, inf=1e18;
vector <ll> A[maxn];
ll x[maxn], l[maxn], r[maxn], w[maxn], dis[maxn];
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
ll n, m; cin >> n >> m;
for (ll i=1; i<=m; i++)
cin >> x[i] >> l[i] >> r[i] >> w[i], dis[i]=inf;
for (ll i=1; i<=m; i++)
for (ll j=1; j<=m; j++)
if (l[j]<=r[i]-abs(x[i]-x[j])+1)
A[i].pb(j);
priority_queue <pll, vector <pll>, greater<pll>> q;
for (ll i=1; i<=m; i++)
if (l[i]==1) dis[i]=w[i], q.push({dis[i], i});
while (!q.empty())
{
ll u=q.top().se, disu=q.top().fi; q.pop();
if (dis[u]!=disu) continue;
for (ll v:A[u])
if (dis[v]>disu+w[v])
dis[v]=disu+w[v], q.push({dis[v], v});
}
ll ans=inf;
for (ll i=1; i<=m; i++)
if (r[i]==n) ans=min(ans, dis[i]);
if (ans==inf) cout << "-1";
else cout << ans;
}
