#include "bits/stdc++.h"
#define here cerr<<"===========================================\n"
#define dbg(x) cerr<<#x<<": "<<x<<endl;
//#include <ext/pb_ds/tree_policy.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
#define ld double
#define ll long long
#define llinf 100000000000000000LL // 10^17
#define pb push_back
#define popb pop_back
#define fi first
#define sc second
#define endl '\n'
#define pll pair<ll,ll>
#define pld pair<ld,ld>
#define sz(a) (ll)(a.size())
#define all(a) a.begin(),a.end()
#define ceri(a,l,r) {cerr<<#a<<": ";for(ll i_ = l;i_<=r;i_++) cerr<<a[i_]<< " ";cerr<<endl;}
#define cer(a) {cerr<<#a<<": ";for(ll x_ : a) cerr<<x_<< " ";cerr<<endl;}
#define daj_mi_malo_vremena ios_base::sync_with_stdio(false);cerr.tie(0);cout.tie(0);cin.tie(0);
using namespace std;
//using namespace __gnu_pbds;
/*
ll add(ll x,ll y){
x+=y;
if(x<0){
x%=mod;
x+=mod;
}else{
if(x>=mod) x%=mod;
}
return x;
}
ll mul(ll a,ll b){
ll ans = (a*b)%mod;
if(ans<0) ans+=mod;
return ans;
}
typedef tree<int,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
typedef tree<int,null_type,less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_multiset;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll rnd(ll l,ll r){
return uniform_int_distribution<ll>(l,r)(rng);
}
*/
#define maxn 100005
#define maxx 400025
ll n,m;
struct tupl{
ll t,l,r,c;
} a[maxn];
ll tsz = 1,tsz2 = 1;
pll t[4*maxn],t2[4*maxn];
void upd(ll v,ll tl,ll tr,ll i,pll p){
if(tl==tr){t[v] = p;return;}
ll mid = (tl+tr)/2;
if(i<=mid) upd(2*v,tl,mid,i,p);
else upd(2*v+1,mid+1,tr,i,p);
t[v] = min(t[2*v],t[2*v+1]);
}
void upd2(ll v,ll tl,ll tr,ll i,pll p){
if(tl==tr){t2[v] = p;return;}
ll mid = (tl+tr)/2;
if(i<=mid) upd2(2*v,tl,mid,i,p);
else upd2(2*v+1,mid+1,tr,i,p);
t2[v] = min(t2[2*v],t2[2*v+1]);
}
pll get(ll v,ll tl,ll tr,ll l,ll r){
if(l>r) return {llinf,0};
if(tl==l&&tr==r) return t[v];
ll mid = (tl+tr)/2;
return min(get(2*v,tl,mid,l,min(mid,r)),get(2*v+1,mid+1,tr,max(mid+1,l),r));
}
pll get2(ll v,ll tl,ll tr,ll l,ll r){
if(l>r) return {llinf,0};
if(tl==l&&tr==r) return t2[v];
ll mid = (tl+tr)/2;
return min(get2(2*v,tl,mid,l,min(mid,r)),get2(2*v+1,mid+1,tr,max(mid+1,l),r));
}
bool cmp(tupl x,tupl y){
return x.t<y.t;
}
ll d[maxn];
set<ll> st;
map<ll,ll> mni,mxi;
ll it = 0;
ll mxt;
void del(ll i){
upd(1,1,mxt,i,{llinf,0});
upd2(1,1,mxt,i,{llinf,0});
}
void tc(){
cin >> m >> n;
mxt = n;
for(ll i = 1;i<=n;i++) cin >> a[i].t >> a[i].l >> a[i].r >> a[i].c;
sort(a+1,a+1+n,cmp);
for(ll i = 1;i<=n;i++) mni[a[i].t] = llinf;
for(ll i = 1;i<=n;i++) mni[a[i].t] = min(mni[a[i].t],i);
for(ll i = 1;i<=n;i++) mxi[a[i].t] = 0;
for(ll i = 1;i<=n;i++) mxi[a[i].t] = max(mxi[a[i].t],i);
for(ll i = 1;i<=n;i++) a[i].l--;
for(ll i = 1;i<=n;i++) del(i);
for(ll i = 1;i<=n;i++){
if(a[i].l==0) continue;
upd(1,1,mxt,i,{a[i].t+a[i].l,i});
upd2(1,1,mxt,i,{-a[i].t+a[i].l,i});
}
for(ll i = 1;i<=n;i++) d[i] = llinf;
priority_queue<pll> pq;
for(ll i = 1;i<=n;i++){
if(a[i].l==0){
d[i] = a[i].c;
pq.push({-d[i],i});
}
}
while(sz(pq)){
pll p = pq.top();
ll i = p.sc;
pq.pop();
if(-p.fi!=d[i]) continue;
p = get(1,1,mxt,mni[a[i].t],mxt);
ll x = a[i].r+a[i].t;
while(p.fi<=x){
ll j = p.sc;
del(j);
d[j] = d[i] + a[j].c;
pq.push({-d[j],j});
p = get(1,1,mxt,mni[a[i].t],mxt);
}
p = get2(1,1,mxt,1,mxi[a[i].t]);
x = a[i].r-a[i].t;
while(p.fi<=x){
ll j = p.sc;
del(j);
d[j] = d[i] + a[j].c;
pq.push({-d[j],j});
p = get2(1,1,mxt,1,mxi[a[i].t]);
}
}
ll ans = llinf;
for(ll i = 1;i<=n;i++) if(a[i].r==m) ans = min(ans,d[i]);
if(ans==llinf) ans = -1;
cout<<ans<<endl;
}
int main(){
daj_mi_malo_vremena
int t; t = 1;
while(t--){
tc();
}
return 0;
}
