#include<bits/stdc++.h>
#pragma GCC optimize("unroll-loops,no-stack-protector")
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
const ll MOD=1e9+7;
const ll MOD2=998244353;
const ll N=1e5+5;
const ll K=350;
const ld pi=acos(-1);
const ll INF=(1LL<<60);
#define SQ(i) ((i)*(i))
#define REP(i,n) for(ll i=0;i<n;i++)
#define REP1(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define X first
#define Y second
#define setp setprecision
#define lwb lower_bound
#define SZ(_a) (ll)_a.size()
ll n,m,dis[N],C[N],T[N],L[N],R[N],ans=INF;
vector<ll> v[N];
priority_queue<pll,vector<pll>,greater<pll> > pq;
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>m;
REP1(i,m){
cin>>T[i]>>L[i]>>R[i]>>C[i];
}
REP1(i,m)REP1(j,m){
if(T[i]>=T[j]&&R[i]-T[i]>=L[j]-T[j]-1){
v[i].pb(j);
}else if(T[i]<T[j]&&R[i]+T[i]>=L[j]+T[j]-1){
v[i].pb(j);
}
}
REP1(i,m){
if(L[i]==1)pq.push(mp(dis[i]=C[i],i));
else dis[i]=INF;
}
while(SZ(pq)){
ll x=pq.top().Y,y=pq.top().X;pq.pop();
if(y>dis[x])continue;
//cout<<dis[x]<<" "<<x<<"\n";
for(auto i:v[x]){
if(dis[i]>y+C[i]){
//cout<<x<<"->"<<i<<"\n";
pq.push(mp(dis[i]=y+C[i],i));
}
}
}
REP1(i,m)if(R[i]==n)ans=min(ans,dis[i]);
cout<<(ans==INF?-1:ans)<<"\n";
return 0;
}
