#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/trie_policy.hpp>
#define pb push_back
#define mp make_pair
#define taskname "A"
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef tree <int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
const int maxn = 1e5 + 10;
int n , m;
struct project{
int t , l , r , c , id;
int t1;
}a[maxn];
ll dis[maxn];
priority_queue<pair<ll,int>,vector<pair<ll,int>>,greater<pair<ll,int>>> pq;
template<char T>
struct BIT{
vector<ii> val[maxn];
void add(int x , ii y){
if(T){
for( ; x > 0 ; x &= x - 1)
val[x].pb(y);
}else{
for( ; x < maxn ; x += x & -x)
val[x].pb(y);
}
}
void update_dis(int u , ll d){
d += a[u].c;
// cout << u << " " << d << endl;
if(dis[u] > d){
dis[u] = d;
pq.push(mp(d , u));
}
}
void del(int x , int y , ll dis){
if(T){
for( ; x < maxn ; x += x & -x){
while(val[x].size() > 0 && val[x].back().first <= y){
update_dis(val[x].back().second , dis);
val[x].pop_back();
}
}
}else{
for( ; x > 0 ; x &= x - 1){
while(val[x].size() > 0 && val[x].back().first <= y){
update_dis(val[x].back().second , dis);
val[x].pop_back();
}
}
}
}
};
BIT<0> s;
BIT<1> s1;
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
if(fopen(taskname".INP","r")){
freopen(taskname".INP", "r",stdin);
freopen(taskname".OUT", "w",stdout);
}
fill_n(dis,maxn,1e18);
cin >> n >> m;
vector<int> val;
for(int i = 0 ; i < m ; ++i){
cin >> a[i].t >> a[i].l >> a[i].r >> a[i].c;
a[i].id = i;
a[i].l--;
val.pb(a[i].t);
}
sort(val.begin(),val.end());
for(int i = 0 ; i < m ; ++i){
a[i].t1 = lower_bound(val.begin(),val.end(),a[i].t) - val.begin() + 1;
}
sort(a , a + m , [&](const project x , const project y){
return x.t + x.l > y.t + y.l;
});
for(int i = 0 ; i < m ; ++i){
s1.add(a[i].t1,mp(a[i].t + a[i].l , a[i].id));
}
sort(a , a + m , [&](const project x , const project y){
return x.l - x.t > y.l - y.t;
});
for(int i = 0 ; i < m ; ++i){
s.add(a[i].t1,mp(a[i].l - a[i].t , a[i].id));
}
sort(a , a + m , [&](const project x , const project y){
return x.id < y.id;
});
ll res = 1e18;
for(int i = 0 ; i < m ; ++i){
if(a[i].l == 0){
dis[i] = a[i].c;
pq.push(mp(dis[i] , i));
}
}
while(pq.size()){
auto u = pq.top();pq.pop();
if(u.first != dis[u.second])continue;
int i = u.second;
// cout << i << endl;
s1.del(a[i].t1 , a[i].r + a[i].t , u.first);
s.del(a[i].t1 , a[i].r - a[i].t , u.first);
}
for(int i = 0 ; i < m ; ++i){
if(a[i].r == n){
// cout << i << " " << dis[i] << endl;
res = min(res , dis[i]);
}
}
if(res == 1e18)cout << -1;
else cout << res;
}
