#include <bits/stdc++.h>
using namespace std;
const int Nmax = 2e5 + 5;
vector<int> last[Nmax];
int n;
int score1[Nmax], score2[Nmax], id1[Nmax], id2[Nmax];
#define left_son (node<<1)
#define right_son ((node<<1)|1)
#define mid ((st+dr)>>1)
class SegTree
{
int a[Nmax<<2], lazy[Nmax<<2];
void propag(int node)
{
if(!lazy[node]) return;
lazy[left_son] += lazy[node];
lazy[right_son] += lazy[node];
a[left_son] += lazy[node];
a[right_son] += lazy[node];
lazy[node] = 0;
}
public:
void update(int node, int st, int dr, int L, int R, int add)
{
if(L <= st && dr <= R)
{
lazy[node] += add;
a[node] += add;
return;
}
propag(node);
if(L <= mid) update(left_son, st, mid, L, R, add);
if(mid < R) update(right_son, mid+1, dr, L, R, add);
a[node] = min(a[left_son], a[right_son]);
}
bool good()
{
return a[1] >= 0;
}
} aint;
int solve()
{
int i, j = 0;
int matches = 0;
for(i=1; i<=n; ++i)
{
while(j<n && score1[i] <= score2[j+1])
{
++j;
aint.update(1, 1, n, j, n, +1);
last[id2[j]].push_back(j);
}
if(last[id1[i]].empty())
{
aint.update(1, 1, n, j, n, -1);
continue;
}
int pos = last[id1[i]].back();
aint.update(1, 1, n, pos, n, -1);
if(aint.good())
{
++matches;
last[id1[i]].pop_back();
}
else
{
aint.update(1, 1, n, pos, n, +1);
aint.update(1, 1, n, j, n, -1);
}
}
return matches;
}
int main()
{
// freopen("input", "r", stdin);
cin.tie(0); cin.sync_with_stdio(false);
cin >> n;
int i;
for(i=1; i<=n; ++i) cin >> id1[i] >> score1[i];
for(i=1; i<=n; ++i) cin >> id2[i] >> score2[i];
cout << n - solve() << '\n';
return 0;
}
