#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif
const int M = 1e5 + 5, MAX = 2e9 + 2;
const long long inf = 1e18;
int n, m, k;
int t[M], l[M], r[M], c[M], pos[M];
array<int, 2> A[4 * M], B[4 * M];
bool del[M];
long long d[M];
vector<array<int, 2>> pf[M], sf[M];
void upd(vector<array<int, 2>> &cands) {
while (cands.size() > 1 && del[cands.back()[1]]) {
cands.pop_back();
}
}
void pul(int id) {
A[id] = min(A[id * 2], A[id * 2 + 1]);
B[id] = min(B[id * 2], B[id * 2 + 1]);
}
void bld(int id = 1, int l = 1, int r = k) {
if (l == r) {
A[id] = pf[l].back();
B[id] = sf[l].back();
return;
}
int md = (l + r) / 2;
bld(id * 2, l, md);
bld(id * 2 + 1, md + 1, r);
pul(id);
}
void ers(int i, int id = 1, int l = 1, int r = k) {
if (l == r) {
upd(pf[i]);
upd(sf[i]);
A[id] = pf[i].back();
B[id] = sf[i].back();
return;
}
int md = (l + r) / 2;
if (i <= md) {
ers(i, id * 2, l, md);
} else {
ers(i, id * 2 + 1, md + 1, r);
}
pul(id);
}
array<int, 2> qry(int u, int v, array<int, 2> *s, int id = 1, int l = 1, int r = k) {
if (u <= l && r <= v) {
return s[id];
}
int md = (l + r) / 2;
if (v <= md) {
return qry(u, v, s, id * 2, l, md);
}
if (md < u) {
return qry(u, v, s, id * 2 + 1, md + 1, r);
}
return min(qry(u, v, s, id * 2, l, md), qry(u, v, s, id * 2 + 1, md + 1, r));
}
int main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m;
vector<int> comp;
for (int i = 1; i <= m; ++i) {
cin >> t[i] >> l[i] >> r[i] >> c[i];
comp.push_back(t[i]);
}
sort(comp.begin(), comp.end());
comp.erase(unique(comp.begin(), comp.end()), comp.end());
k = comp.size();
for (int i = 1; i <= m; ++i) {
pos[i] = lower_bound(comp.begin(), comp.end(), t[i]) - comp.begin() + 1;
pf[pos[i]].push_back({l[i] - t[i], i});
sf[pos[i]].push_back({l[i] + t[i], i});
}
for (int i = 1; i <= k; ++i) {
pf[i].push_back({MAX, -1});
sf[i].push_back({MAX, -1});
sort(pf[i].rbegin(), pf[i].rend());
sort(sf[i].rbegin(), sf[i].rend());
}
using T = pair<long long, int>;
priority_queue<T, vector<T>, greater<T>> pq;
bld();;
fill(d + 1, d + m + 1, inf);
for (int i = 1; i <= m; ++i) {
if (l[i] == 1) {
del[i] = 1;
ers(pos[i]);
pq.push({d[i] = c[i], i});
}
}
while (pq.size()) {
auto [x, u] = pq.top(); pq.pop();
if (x != d[u]) {
continue;
}
while (1) {
auto dat = qry(1, pos[u], A);
if (dat[0] > r[u] - t[u] + 1) {
break;
}
int v = dat[1];
pq.push({d[v] = x + c[v], v});
del[v] = 1;
ers(pos[v]);
}
while (1) {
auto dat = qry(pos[u], k, B);
if (dat[0] > r[u] + t[u] + 1) {
break;
}
int v = dat[1];
pq.push({d[v] = x + c[v], v});
del[v] = 1;
ers(pos[v]);
}
}
auto res = inf;
for (int i = 1; i <= m; ++i) {
if (r[i] == n) {
res = min(res, d[i]);
}
}
cout << (res == inf ? -1 : res);
return 0;
}
