#include <bitset>
#include <functional>
#include <iostream>
#include <map>
#include <unordered_map>
#include <vector>
#include <algorithm>
#include <array>
using namespace std;
template <typename T>
class segment_tree {
public:
int siz = 1;
vector <T> segtree;
function <T(T, T)> merge;
segment_tree(function <T(T, T)> IN) : merge (IN) {}
void resize (int n) {
while (siz < n)
siz *= 2;
segtree.resize (2 * siz);
}
void update (int ind, T K) {
int u = siz + ind - 1;
segtree[u] = merge (segtree[u], K);
u /= 2;
while (u)
segtree[u] = merge (
segtree[2 * u], segtree[2 * u + 1]
), u /= 2;
}
T get (int L, int R, int u, int l, int r) {
if (r < L || R < l)
return T();
if (L <= l && r <= R)
return segtree[u];
const int m = (l + r) / 2;
return merge (
get (L, R, 2 * u, l, m),
get (L, R, 2 * u + 1, m + 1, r)
);
}
T get (int L, int R) {
return get (L, R, 1, 1, siz);
}
};
int main () {
ios::sync_with_stdio (false);
cin.tie (0);
cout.tie (0);
const int lim = 4e5 + 20;
int N = 0;
cin >> N;
vector <array <int, 4> > v (N + 1);
for (int i = 1; i <= N; i++)
cin >> v[i][0] >> v[i][1] >> v[i][2] >> v[i][3];
[&]()->void {
map <int, int> m;
for (array <int, 4>& e : v)
m[e[0]] = 0, m[e[1]] = 0, m[e[2]] = 0, m[e[3]] = 0;
int free = 0;
for (pair <const int, int>& e : m)
e.second = ++free;
for (array <int, 4>& e : v) {
e[0] = m[e[0]];
e[1] = m[e[1]];
e[2] = m[e[2]];
e[3] = m[e[3]];
}
}();
// add compression :3
vector <array <int, 4> > byFirst (lim + 1);
for (int i = 1; i <= N; i++)
byFirst[v[i][0]] = v[i];
segment_tree <int> segtree (
[](int a, int b) {
return max (a, b);
}
);
segtree.resize (lim + 1);
vector <vector <pair <int, int> > > tasks (lim + 1);
for (int i = 1; i <= lim; i++) {
for (pair <int, int>& e : tasks[i])
segtree.update (e.first, e.second);
if (byFirst[i][0] == i) {
int curans = segtree.get (1, byFirst[i][2]) + 1;
tasks[byFirst[i][1]].emplace_back (byFirst[i][3], curans);
}
}
cout << segtree.get (1, lim) << '\n';
}
