#include <bits/stdc++.h>
using namespace std;
using ll = long long;
pair<int, int> a[100100];
int b[100100];
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int n, m;
cin >> n >> m;
for (int i = 1;i <= n;i++) cin >> a[i].second >> a[i].first;
for (int i = 1;i <= m;i++) cin >> b[i];
sort(a + 1, a + 1 + n, greater<pair<int, int>>());
sort(b + 1, b + 1 + m);
int ans = m + 1;
for (int i = 1;i <= n;i++) {
int idx = lower_bound(b + 1, b + 1 + m, a[i].second) - b;
if (ans - 1 >= idx) ans--;
}
cout << m - ans + 1;
return 0;
}
