#include <bits/stdc++.h>

using namespace std;
ifstream f("ograzi.in");
ofstream g("ograzi.out");
struct eveniment
{
    int tip,x,y;
};
int n,m,h,w;
bool cmp(eveniment a, eveniment b)
{
    return a.x<b.x;
}
int main()
{
    f>>n>>m>>w>>h;
    vector <eveniment> eves;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        f>>x>>y;
        eves.push_back(eveniment{1,x,y});
    }
    for(int i=1;i<=m;i++)
    {
        int x,y;
        f>>x>>y;
        eves.push_back(eveniment{2,x,y+h});
        eves.push_back(eveniment{3,x+w,y+h});
    }
    int nr=0;
    set <int> s;
    sort(eves.begin(),eves.end(),cmp);
    for(auto e : eves)
    {
        if(e.tip==2)
        {
            s.insert(e.y);
        }
        else if(e.tip==3)
        {
            s.erase(e.y);
        }
        else if(e.tip==1)
        {
            set <int> :: iterator it = s.lower_bound(e.y);
            if(*it-e.y<=h)
            {
                ++nr;
            }
        }
    }
    g<<nr<<'\n';
    return 0;
}