// UUID: 9babfc7c-ef7b-47b7-b999-09fff53d30b5
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
int main() {
int n, m;
cin >> n >> m;
vector<pii> kep(n);
for(auto &x : kep){
cin >> x.first >> x.second;
}
vector<int> keret(m);
for(int &x : keret){
cin >> x;
}
sort(kep.begin(), kep.end(), [&](pii a, pii b){
if(a.second == b.second){
return a.first < b.first;
}
return a.second < b.second;
});
sort(keret.begin(), keret.end());
int ind = m - 1;
for(int i = n - 1; i >= 0; i--){
if(kep[i].first <= keret[ind]){
ind--;
}
if(ind < 0){
break;
}
}
cout << m - ind - 1 << "\n";
}
