// Zende bad Shoma nasime faghat !
#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'
using namespace std;
typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;
const ll Mod = 1000000007LL;
const int N = 2e5 + 10;
const ll Inf = 2242545357980376863LL;
const ll Log = 30;
int n, m;
int T[N], L[N], R[N], C[N], mk[N];
ll dis[N];
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m;
for(int i = 1; i <= m; i++) cin >> T[i] >> L[i] >> R[i] >> C[i];
ll ans = Inf;
memset(dis, 31, sizeof dis);
for(int i = 1; i <= m; i++){
if(L[i] == 1) dis[i] = C[i];
}
while(true){
ll mn = Inf, idx = -1;
for(int i = 1; i <= m; i++){
if(mk[i]) continue;
if(dis[i] < mn){
mn = dis[i];
idx = i;
}
}
if(idx == -1) break;
mk[idx] = 1;
if(R[idx] == n) ans = min(ans, dis[idx]);
for(int j = 1; j <= m; j++){
if(L[j] > R[idx] + 1) continue;
if(mk[j]) continue;
if(T[j] <= T[idx]){
if(L[j] + (T[idx] - T[j]) <= R[idx] + 1)
dis[j] = min(dis[j], dis[idx] + C[j]);
}
if(T[j] > T[idx]){
if(R[idx] - (T[j] - T[idx]) >= L[j] - 1)
dis[j] = min(dis[j], dis[idx] + C[j]);
}
}
}
if(ans >= Inf) return cout << "-1\n", 0;
cout << ans << '\n';
return 0;
}
