#include <bits/stdc++.h>
#include <iostream>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<ll,null_type,less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> order_set;
mt19937 mt_rand(chrono::high_resolution_clock::now().time_since_epoch().count());
//uniform_int_distribution<int> gen; ///(min, max)
//int random() {return gen(mt_rand);}
const int mxN=2e5+5;
const int mod=998244353;
const int mxlogN=40;
const int mxK=26;
const int inf=2e9;
const int K=600;
pair<int,int> a[mxN];
int b[mxN];
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m; cin >> n >> m;
for(int i=0; i<n; i++) cin >> a[i].second >> a[i].first;
sort(a,a+n);
for(int i=0; i<m; i++) cin >> b[i];
sort(b,b+m);
int j=m-1;
for(int i=n-1; i>=0; i--) if(~j&&a[i].second<=b[j]) j--;
cout << m-1-j << "\n";
}
