#include<bits/stdc++.h>
#define fi first
#define se second
#define int long long
using namespace std;
using ll = long long;
using ii = pair<int, int>;
using aa = array<int,3>;
const int N = 1e5+5;
int n, m, ans = 0;
int c[N];
ii p[N];
bool cmp(ii a,ii b){
if (a.se == b.se) return a.fi < b.fi;
return a.se < b.se;
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
cin >> n >> m;
for (int i = 1; i <= n; i++) cin >> p[i].fi >> p[i].se;
for (int i = 1; i <= m; i++) cin >> c[i];
sort(p+1,p+1+n,cmp);
sort(c+1,c+1+m);
int cur = m;
for (int i = n; i >= 1; i--){
if (p[i].fi <= c[cur]) cur--;
}
cout << m - cur;
return 0;
}
