#include <bits/stdc++.h>
using namespace std;
const int N=2510;
struct cow{
    int maxx,minn;
}a[N];
struct sp{
    int spf,cov;
}b[N];
bool cmp(cow a,cow b){
    return a.maxx>b.maxx;
}
int c,l,ans,maxx;
int main(){
    freopen("tanning.in","r",stdin);
    freopen("tanning.out","w",stdout);    
    cin>>c>>l;
    for(int i=1;i<=c;i++){
        cin>>a[i].minn>>a[i].maxx;
    }
    sort(a+1,a+c+1,cmp);
    for(int i=1;i<=l;i++){
        cin>>b[i].spf>>b[i].cov;           
	}	
	for(int i=1;i<=c;i++){
	    maxx=0;
        for(int j=1;j<=l;j++){
            if(b[i].spf>=a[i].minn&&b[i].spf<=a[i].maxx&&b[i].cov>0){
                if(maxx<b[i].spf){
                    maxx=i;         
                }
            }
        }
        if(maxx!=0){
            b[maxx].cov--;
            ans++;
        }
    }
	cout<<ans;
    
    return 0;
}