#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 100005;
vector<int> dsct;
vector<pair<int, int>> inct[MAXN], dect[MAXN];
int pro[MAXN];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int N, M; cin >> N >> M; N++;
vector<tuple<int, int, int, ll>> pa(M);
for (int i = 0; i < M; i++){
int t, l, r; ll c; cin >> t >> l >> r >> c; r++;
pa[i] = {t, l, r, c};
dsct.push_back(t);
}
sort(dsct.begin(), dsct.end());
dsct.resize(distance(dsct.begin(), unique(dsct.begin(), dsct.end())));
priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> pq;
for (int i = 0; i < M; i++){
int t, l, r; ll c; tie(t, l, r, c) = pa[i];
int tid = lower_bound(dsct.begin(), dsct.end(), t) - dsct.begin() + 1;
for (int x = M - tid + 1; x <= M; x += (x & -x)) inct[x].push_back({l + t, i});
for (int x = tid; x <= M; x += (x & -x)) dect[x].push_back({l - t, i});
if (l == 1){
pro[i] = 1; pq.push({c, i});
}
}
for (int i = 1; i <= M; i++){
sort(inct[i].begin(), inct[i].end(), greater<pair<ll, int>>());
sort(dect[i].begin(), dect[i].end(), greater<pair<ll, int>>());
}
while (!pq.empty()){
ll cc; int cn; tie(cc, cn) = pq.top(); pq.pop();
int t, l, r; tie(t, l, r, ignore) = pa[cn];
if (r == N){
cout << cc; return 0;
}
int tid = lower_bound(dsct.begin(), dsct.end(), t) - dsct.begin() + 1;
for (int x = M - tid + 1; x; x -= (x & -x))
while (!inct[x].empty() && inct[x].back().first <= r + t){
int nn = inct[x].back().second; inct[x].pop_back();
if (pro[nn]) continue;
pro[nn] = 1; pq.push({cc + get<3>(pa[nn]), nn});
}
for (int x = tid; x; x -= (x & -x))
while (!dect[x].empty() && dect[x].back().first <= r - t){
int nn = dect[x].back().second; dect[x].pop_back();
if (pro[nn]) continue;
pro[nn] = 1; pq.push({cc + get<3>(pa[nn]), nn});
}
}
cout << -1;
}
