#include <bits/stdc++.h>
using namespace std;
const int MAXM = 262144;
int N, M;
int T[MAXM], L[MAXM], R[MAXM], C[MAXM];
int XL[MAXM], YL[MAXM], XR[MAXM], YR[MAXM];
bool vis[MAXM];
set<pair<int, int> > idx[2*MAXM];
bool in[MAXM];
void pushc(int x, int y, int i)
{
//printf("PUSH %d %d %d\n", x, y, i);
x += MAXM;
while(x)
{
idx[x].emplace(y, i);
x /= 2;
}
in[i] = true;
}
vector<int> popc(int x, int y)
{
vector<int> ret;
int f = MAXM, t = x+MAXM;
while(f<=t && t)
{
if(t%2==0 || f==t)
{
auto it = idx[t].begin();
while(it != idx[t].end())
{
auto [val, iv] = *it;
if(val>y) break;
if(in[iv]) ret.push_back(iv), in[iv] = false;
auto pit = it; ++it; idx[t].erase(pit);
}
--t;
}
f/=2; t/=2;
}
/*printf("POP %d %d\n", x, y);
for(auto q: ret) printf("%d ", q);
puts("");*/
return ret;
}
int main()
{
scanf("%d%d", &N, &M);
vector<int> x, y;
for(int i=0; i<M; ++i)
{
scanf("%d%d%d%d", T+i, L+i, R+i, C+i);
--L[i]; //L[i] = 0, R[i] = N covers whole
XL[i] = L[i]-T[i], YL[i] = L[i]+T[i];
XR[i] = R[i]-T[i], YR[i] = R[i]+T[i];
x.push_back(XL[i]); x.push_back(XR[i]);
y.push_back(YL[i]); y.push_back(YR[i]);
}
sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
sort(y.begin(), y.end()); y.erase(unique(y.begin(), y.end()), y.end());
for(int i=0; i<M; ++i)
{
XL[i] = lower_bound(x.begin(), x.end(), XL[i]) - x.begin();
XR[i] = lower_bound(x.begin(), x.end(), XR[i]) - x.begin();
YL[i] = lower_bound(y.begin(), y.end(), YL[i]) - y.begin();
YR[i] = lower_bound(y.begin(), y.end(), YR[i]) - y.begin();
}
using pli = pair<long long, int>;
priority_queue<pli, vector<pli>, greater<pli>> Q;
for(int i=0; i<M; ++i)
if(L[i] == 0)
vis[i] = true, Q.emplace((long long)C[i], i);
else
pushc(XL[i], YL[i], i);
while(!Q.empty())
{
auto [cost, idx] = Q.top(); Q.pop();
if(R[idx] == N) return printf("%lld\n", cost), 0;
vector<int> idxs = popc(XR[idx], YR[idx]);
for(auto i: idxs)
{
vis[i] = true;
Q.emplace(cost+C[i], i);
}
}
puts("-1");
}
