// Starcraft 2 enjoyer //
#include <bits/stdc++.h>
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
#define LSOne(X) ((X) & -(X))
#define int long long
const int N = 2e5 + 5;
const int M = 2e6 + 5;
const int O = 1e6;
const long long K = 2;
const int LG = 60;
const long long INF = 1e18 + 5;
const int C = 26;
const int B = 1000;
const int MOD = 1e9 + 7;
struct SegmentTree
{
vector<int> st;
int n;
void update(int v, int val, int pos, int l, int r)
{
if (l == r)
{
st[v] = min(st[v], val);
}
else
{
int m = (l + r) / 2;
if (pos <= m)
{
update(2 * v, val, pos, l, m);
}
else
{
update(2 * v + 1, val, pos, m + 1, r);
}
st[v] = min(st[2 * v], st[2 * v + 1]);
}
}
int get(int v, int l, int r, int tl, int tr)
{
if (tl > tr)
return INF;
if (tl <= l && r <= tr)
{
return st[v];
}
else
{
int m = (l + r) / 2;
return min(get(2 * v, l, m, tl, min(tr, m)), get(2 * v + 1, m + 1, r, max(tl, m + 1), tr));
}
}
SegmentTree(int len)
{
n = len;
st.assign(4 * n, INF);
}
void update(int val, int pos)
{
update(1, val, pos, 0, n - 1);
}
int get(int l, int r)
{
return get(1, 0, n - 1, l, r);
}
};
int m, n, ans;
array<int, 4> line[N];
vector<int> v;
inline void solve()
{
cin >> m >> n;
for (int x = 0; x < n; x++)
{
int a, b, c, d;
cin >> a >> b >> c >> d;
line[x] = {a, b, c, d};
v.push_back(a);
v.push_back(c);
v.push_back(b);
}
v.push_back(1);
v.push_back(n);
sort(v.begin(), v.end());
v.erase(unique(v.begin(), v.end()), v.end());
SegmentTree mn(v.size()), mx(v.size());
mn.update(0, 0);
mx.update(0, v.size() - 1);
ans = INF;
for (int x = 0; x < n; x++)
{
auto [a, b, c, d] = line[x];
a = lower_bound(v.begin(), v.end(), a) - v.begin();
b = lower_bound(v.begin(), v.end(), b) - v.begin();
c = lower_bound(v.begin(), v.end(), c) - v.begin();
int i = mn.get(a, b), j = mx.get(a, b);
if (i != INF && j != INF)
{
ans = min(ans, i + j + d);
}
if (i != INF)
{
mn.update(i + d, c);
}
if (j != INF)
{
mx.update(j + d, c);
}
}
if(ans == INF)
{
cout << -1 << "\n";
}
else
{
cout << ans << "\n";
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
for (int x = 1; x <= t; x++)
{
solve();
}
return 0;
}
