#include<bits/stdc++.h>
using ll = long long;
using namespace std;
#define pll pair <ll,ll>
#define fi first
#define se second
#define MP make_pair
#define sz(a) (ll((a).size()))
#define BIT(mask,i) (((mask) >> (i))&1)
#define MASK(i) (1LL << (i))
const ll MAXN = 1e5+100;
const ll INF = 1e18;
ll dp[MAXN];
struct treatment{
ll t,l,r,c;
};
treatment a[MAXN];
vector <pll> tree1[MAXN*4],tree2[MAXN*4];
vector <ll> val_t;
void update(ll id,ll l,ll r,ll pos){
if (val_t[l] > a[pos].t || val_t[r] < a[pos].t)return;
tree1[id].push_back(MP(a[pos].l - a[pos].t,pos));
tree2[id].push_back(MP(a[pos].l + a[pos].t,pos));
if (l == r){
return;
}
ll mid = (l + r) >> 1;
update(id<<1,l,mid,pos);
update(id<<1|1,mid+1,r,pos);
}
void build(ll id,ll l,ll r){
sort(tree1[id].begin(),tree1[id].end(),greater <>());
sort(tree2[id].begin(),tree2[id].end(),greater <>());
if (l != r){
ll mid = (l + r) >> 1;
build(id<<1,l,mid);
build(id<<1|1,mid+1,r);
}
}
vector <ll> all;
void get1(ll id,ll l,ll r,ll pos){
if (val_t[l] > a[pos].t)return;
if (val_t[r] <= a[pos].t){
while (!tree1[id].empty() && tree1[id].back().fi <= a[pos].r - a[pos].t + 1){
all.push_back(tree1[id].back().se);
tree1[id].pop_back();
}
return;
}
ll mid = (l + r) >> 1;
get1(id<<1,l,mid,pos);
get1(id<<1|1,mid+1,r,pos);
}
void get2(ll id,ll l,ll r,ll pos){
if (val_t[r] < a[pos].t)return;
if (val_t[l] >= a[pos].t){
while (!tree2[id].empty() && tree2[id].back().fi <= a[pos].r + a[pos].t + 1){
all.push_back(tree2[id].back().se);
tree2[id].pop_back();
}
return;
}
ll mid = (l + r) >> 1;
get2(id<<1,l,mid,pos);
get2(id<<1|1,mid+1,r,pos);
}
ll n,m;
int main(){
ios_base::sync_with_stdio(0);cin.tie(nullptr);
cin>>n>>m;
for (ll i = 1;i <= m;i ++){
cin>>a[i].t>>a[i].l>>a[i].r>>a[i].c;
val_t.push_back(a[i].t);
}
sort(val_t.begin(),val_t.end());
val_t.resize(unique(val_t.begin(),val_t.end())-val_t.begin());
val_t.insert(val_t.begin(),0);
for (ll i = 1;i <= m;i ++)update(1,1,sz(val_t)-1,i);
build(1,1,sz(val_t)-1);
priority_queue <pll,vector <pll> ,greater <> > q;
for (ll i = 1;i <= m;i ++){
if (a[i].l == 1){dp[i] = a[i].c;q.push(MP(a[i].c,i));}
else dp[i] = INF;
}
while (!q.empty()){
ll u = q.top().se;
q.pop();
all.clear();
get1(1,1,sz(val_t)-1,u);
get2(1,1,sz(val_t)-1,u);
for (auto v:all){
// cout<<v<<
if (dp[v] == INF){
dp[v] = dp[u] + a[v].c;
q.push(MP(dp[v],v));
}
}
}
ll ans = INF;
for (ll i = 1;i <= m;i ++)if (a[i].r == n)ans = min(ans,dp[i]);
if (ans == INF)ans = -1;
cout<<ans;
}
