// M
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 100005;
int n, m, T[N], L[N], R[N], C[N], P[N], rev[N];
ll D[N];
vector < int > vec;
priority_queue < pair < ll , int > > Pq;
set < pair < int , int > > ST[2][N];
inline void Add(int w, int i, pair < int , int > val)
{
for (; i < N; i += i & - i)
ST[w][i].insert(val);
}
inline void Get(int w, int i, int ri)
{
for (; i; i -= i & - i)
while (ST[w][i].size() && ST[w][i].begin()->first <= ri)
{
if (D[ST[w][i].begin()->second] == -1)
vec.push_back(ST[w][i].begin()->second);
ST[w][i].erase(ST[w][i].begin());
}
}
int main()
{
scanf("%d%d", &n, &m);
for (int i = 1; i <= m; i ++)
scanf("%d%d%d%d", &T[i], &L[i], &R[i], &C[i]), R[i] ++;
iota(P + 1, P + m + 1, 1);
sort(P + 1, P + m + 1, [&](int i, int j){return T[i] < T[j];});
for (int i = 1; i <= m; i ++)
rev[P[i]] = i;
for (int i = m; i; i --)
Add(0, m - i + 1, make_pair(L[P[i]] + T[P[i]], P[i]));
for (int i = 1; i <= m; i ++)
Add(1, i, make_pair(L[P[i]] - T[P[i]], P[i]));
memset(D, -1, sizeof(D));
for (int i = 1; i <= m; i ++)
if (L[i] == 1)
D[i] = C[i], Pq.push({-D[i], i});
while (Pq.size())
{
ll d = - Pq.top().first;
int v = Pq.top().second;
Pq.pop();
if (R[v] == n + 1)
return !printf("%lld\n", d);
vec.clear();
Get(0, m - rev[v], R[v] + T[v]);
Get(1, rev[v] - 1, R[v] - T[v]);
for (int u : vec)
if (D[u] == -1)
D[u] = D[v] + C[u], Pq.push({-D[u], u});
}
return !printf("-1\n");
}
