/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
#define ff first
#define ss second
#define pii pair<int,int>
#define vi vector<int>
const int N = 1e6+100, M = 1e5+10, K = 52, MX = 30;
const ll INF = 1e18;
int n, m;
array<ll, 4> a[N];
ll dp[N];
void solve(){
cin >> n >> m;
for(int i = 1; i <= m; ++i){
cin >> a[i][2] >> a[i][0] >> a[i][1] >> a[i][3];
}
sort(a+1, a+1+m);
ll ans = INF;
for(int i = 1; i <= m; ++i){
// swap(a[i][0], a[i][1]);
if(a[i][0] == 1){
dp[i] = a[i][3];
if(a[i][1] == n){
ans = min(ans, a[i][3]);
}
}else{
dp[i] = INF;
for(int j = 1; j < i; ++j){
if(a[j][1] >= a[i][0] - 1){
ll t1 = a[j][2];
ll t2 = a[i][2];
if(abs(t1-t2) <= a[j][1] - a[i][0] + 2){
dp[i] = min(dp[i], dp[j] + a[i][3]);
}
}
}
if(a[i][1] == n){
ans = min(ans, dp[i]);
}
}
// cerr << a[i][0] << ' ' << a[i][1] << ' ';
// cerr << i << ' ' << dp[i] << '\n';
}
if(ans==INF){
cout << -1;
}else{
cout << ans;
}
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int tt = 1, aa;
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
while(tt--){
solve();
en;
}
cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
return 0;
}
