#include<bits/stdc++.h>
 using namespace std;
const int MAXN=5000;
struct cow{
   int minSPF,maxSPF;
}c[MAXN];
int SPF[MAXN],cover[MAXN];
int L,C;
int J=0;
bool myc(cow a,cow b) { return a.minSPF>b.minSPF; }
int main()
{
   cin>>C>>L;
   for(int i=1;i<=C;i++) scanf("%d %d",&c[i].minSPF,&c[i].maxSPF);
   sort(c+1,c+C+1,myc);
   for(int i=1;i<=L;i++) scanf("%d %d",&SPF[i],&cover[i]);
   for(int i=1;i<=C;i++)
   {
   	int x=c[i].minSPF,y=c[i].maxSPF;
   	int use=-1,num;
	for(int j=1;j<=L;j++)
   	 if(SPF[j]>=x && SPF[j]<=y && cover[j] && SPF[j]>use )  use=SPF[j],num=j;	
   	if(use!=-1) { J++; cover[num]--;} 
   }
   cout<<J;
}