#include<bits/stdc++.h>
using namespace std;
struct node{int x,y;}a[2600],b[2600];
bool cmp(node n1,node n2){return n1.x!=n2.x?n1.x>n2.x:n1.y>n2.y;}
int main()
{
    int n,m;scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)scanf("%d%d",&a[i].x,&a[i].y);
    for(int i=1;i<=m;i++)scanf("%d%d",&b[i].x,&b[i].y);
    sort(a+1,a+n+1,cmp);
    sort(b+1,b+m+1,cmp);
    int ans=0;
    for(int i=1;i<=n;i++)
    for(int j=1;j<=m;j++)
    {
        if(b[j].y>0&&b[j].x>=a[i].x&&b[j].x<=a[i].y)
        {
            ans++;b[j].y--;break;
        }
        if(b[j].x<a[i].x)break;
    }
    printf("%d\n",ans);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
struct node{int x,y;}a[2600],b[2600];
bool cmp(node n1,node n2){return n1.x!=n2.x?n1.x>n2.x:n1.y>n2.y;}
int main()
{
    int n,m;scanf("%d%d",&n,&m);
    for(int i=1;i<=n;i++)scanf("%d%d",&a[i].x,&a[i].y);
    for(int i=1;i<=m;i++)scanf("%d%d",&b[i].x,&b[i].y);
    sort(a+1,a+n+1,cmp);
    sort(b+1,b+m+1,cmp);
    int ans=0;
    for(int i=1;i<=n;i++)
    for(int j=1;j<=m;j++)
    {
        if(b[j].y>0&&b[j].x>=a[i].x&&b[j].x<=a[i].y)
        {
            ans++;b[j].y--;break;
        }
        if(b[j].x<a[i].x)break;
    }
    printf("%d\n",ans);
    return 0;
}