#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define co cout<<
// stuff
void solve(){
ll n,m;
cin>>n>>m;
pair<ll,ll>arr1[n+5];
ll arr[m+5];
for(int i=0;i<n;i++) cin>>arr1[i].second>>arr1[i].first;
sort(arr1,arr1+n);
reverse(arr1,arr1+n);
for(int i=0;i<m;i++) cin>>arr[i];
sort(arr,arr+m);
reverse(arr,arr+m);
ll ans=0;
for(int i=0,j=0;i<n&&j<m;i++) if(arr1[i].second<arr[j]) j++,ans++;
co ans;
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
int _=1;
// cin>>_;
while(_--) solve();
}
