#include <iostream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <cstring>
#include <chrono>
#include <vector>
#include <map>
#include <random>
#include <set>
#include <algorithm>
#include <math.h>
#include <cstdio>
#include <stdio.h>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <deque>
#include <cassert>
#include <stack>
using namespace std;
#define mp make_pair
#define f first
#define se second
#define pb push_back
#define ppb pop_back
#define ll long long
#define ull unsigned long long
#define cntbit(x) __builtin_popcount(x)
#define endl '\n'
#define uset unordered_set
#define umap unordered_map
#define all(x) x.begin(), x.end()
#define pii pair<int, int>
#define ld long double
#define pll pair<long long, long long>
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline T range(T l, T r) {
return uniform_int_distribution <T>(l, r)(rng);
}
template <typename T> void Min(T &a, T b) {
a = min(a, b);
}
template <typename T> void Max(T &a, T b) {
a = max(a, b);
}
const int mod = 1e9 + 7;
const ll inf = 2e18;
const int N = 1e6 + 15;
int n, m;
ll ans = -1;
vector <int> compress;
int sz;
ll d[N];
set <pair <ll, int>> q;
inline int gt(int x) {
return lower_bound(compress.begin(), compress.end(), x) - compress.begin() + 1;
}
struct pt {
int t, l, r, c;
} a[N];
struct segment_tree {
set <pii> t[N << 2];
void get(int v, int tl, int tr, int l, int r, int val, vector <int> &res) {
if(tl > r || tr < l)
return;
if(tl >= l && tr <= r) {
while(!t[v].empty() && t[v].begin()->f <= val) {
res.pb(t[v].begin()->se);
t[v].erase(t[v].begin());
}
return;
}
int mid = tl + tr >> 1;
get(v << 1, tl, mid, l, r, val, res);
get(v << 1 | 1, mid + 1, tr, l, r, val, res);
}
void update(int v, int tl, int tr, int pos, pii val, bool insert) {
if(insert)
t[v].insert(val);
else if(t[v].find(val) != t[v].end())
t[v].erase(val);
if(tl == tr)
return;
int mid = tl + tr >> 1;
if(pos <= mid)
update(v << 1, tl, mid, pos, val, insert);
else
update(v << 1 | 1, mid + 1, tr, pos, val, insert);
}
} t1, t2;
main() {
fill(d, d + N, inf);
ios_base::sync_with_stdio(0); cout.tie(0); cin.tie(0);
cin >> n >> m;
for(int i = 1; i <= m; ++i) {
cin >> a[i].t >> a[i].l >> a[i].r >> a[i].c;
compress.pb(a[i].t);
}
sort(compress.begin(), compress.end());
compress.erase(unique(compress.begin(), compress.end()), compress.end());
sz = compress.size();
for(int i = 1; i <= m; ++i) {
--a[i].l;
if(a[i].l == 0) {
d[i] = a[i].c;
q.insert({d[i], i});
}
else {
t1.update(1, 1, sz, gt(a[i].t), mp(a[i].l + a[i].t, i), true);
t2.update(1, 1, sz, gt(a[i].t), mp(a[i].l - a[i].t, i), true);
}
}
while(!q.empty()) {
int i = q.begin()->se;
q.erase(q.begin());
vector <int> res[2] = {{}, {}};
t1.get(1, 1, sz, gt(a[i].t), sz, a[i].r + a[i].t, res[0]);
t2.get(1, 1, sz, 1, gt(a[i].t), a[i].r - a[i].t, res[1]);
for(int t = 0; t < 2; ++t) {
for(int j : res[t]) {
d[j] = d[i] + a[j].c;
q.insert(mp(d[j], j));
t1.update(1, 1, sz, gt(a[j].t), mp(a[j].l + a[j].t, j), false);
t2.update(1, 1, sz, gt(a[j].t), mp(a[j].l - a[j].t, j), false);
}
}
}
for(int i = 1; i <= m; ++i) {
if(a[i].r != n || d[i] == inf)
continue;
if(ans == -1 || d[i] < ans)
ans = d[i];
}
cout << ans << endl;
return 0;
}
