//Sylwia Sapkowska
#include <bits/stdc++.h>
using namespace std;
void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
#define int long long
const int oo = 1e18, K = 30;
struct project{
int t, l, r, c;
pair<int, int>L, R;
void read(){
cin >> t >> l >> r >> c;
r++;
L = {t-l, l+t};
R = {t-r, r+t};
// debug(L, R);
}
};
void solve(){
int n, m; cin >> n >> m;
vector<project>a(m);
for (int i = 0; i<m; i++) a[i].read();
vector<int>dist(m, oo);
set<pair<int, int>>s;
for (int i = 0; i<m; i++){
if (a[i].l == 1){
dist[i] = a[i].c;
s.insert({a[i].c, i});
}
}
while (s.size()){
int v = s.begin()->second;
int d = s.begin()->first;
s.erase(s.begin());
if (dist[v] < d) continue;
for (int x = 0; x<m; x++){
if (a[x].L.first >= a[v].R.first && a[x].L.second <= a[v].R.second){
if (dist[x] > d + a[x].c){
dist[x] = d+a[x].c;
s.insert({dist[x], x});
}
}
}
}
int ans = oo;
for (int i = 0; i<m; i++){
if (a[i].r == n+1){
// debug(i, dist[i]);
ans = min(ans, dist[i]);
}
}
if (ans == oo) cout << "-1\n";
else cout << ans << "\n";
}
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
