#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define fi first
#define se second
constexpr ll MAXN=3e5+5,MAXV=3e5,MOD=1e9+7,INF=1e18;
ll n,m,i,j,p,k,ans=INF,dem,st,en,b[MAXN];
struct h{
ll si,c;
} a[MAXN];
bool cmp(h x,h y){
return x.c<y.c||(x.c==y.c&&x.si<y.si);
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n>>m;
for(i=1;i<=n;i++)
cin>>a[i].si>>a[i].c;
for(i=1;i<=m;i++) cin>>b[i];
sort(a+1,a+n+1,cmp);
sort(b+1,b+m+1);
ll cur=m;
for(i=n;i>=1;i--){
if(a[i].si<=b[cur])
cur--;
}
cout<<m-cur;
}
