#include <bits/stdc++.h>
using namespace std;
const int Mmax=1e5+5;
struct tratament
{
int t,l,r,c;
};
tratament trat[Mmax];
bool viz[Mmax];
vector<pair<int,int>> g[Mmax];
int main()
{
int n,m;
cin>>n>>m;
priority_queue<pair<int,int>> pq;
bool ok=1;
for(int i=1;i<=m;i++)
{
cin>>trat[i].t>>trat[i].l>>trat[i].r>>trat[i].c;
if(trat[i].t!=1) ok=0;
if(trat[i].l==1)
{
pq.push({-trat[i].c,i});
}
}
assert(!ok);
for(int i=1;i<=m;i++)
{
for(int j=1;j<=m;j++)
{
if(j==i) continue;
if(trat[i].t<trat[j].t)
{
if(trat[i].r+trat[i].t>=trat[j].l+trat[j].t-1) g[i].push_back({j,trat[j].c});
}
else
{
if(trat[i].r-trat[i].t>=trat[j].l-trat[j].t-1) g[i].push_back({j,trat[j].c});
}
}
}
while(!pq.empty())
{
auto [val,nod]=pq.top();
pq.pop();
if(viz[nod]) continue;
///cout<<nod<<' '<<-val<<'\n';
viz[nod]=1;
if(trat[nod].r==n)
{
cout<<-val<<'\n';
return 0;
}
for(auto [u,cost]:g[nod])
{
if(!viz[u]) pq.push({val-cost,u});
}
}
cout<<-1<<'\n';
return 0;
}
