#include <bits/stdc++.h>
using namespace std;

ifstream fi("ograzi.in");
ofstream fo("ograzi.out");
#define cin fi
#define cout fo

const int NMAX = 1e6 + 10;

int n, m, w, h;
vector < pair<int, int> > dr, oi;
int aib[NMAX];

inline int lsb(int x)
{
    return (x & (-x));
}

void update(int poz, int val)
{
    for (int i = poz; i < NMAX; i += lsb(i))
        aib[i] += val;
}

int getSum(int poz)
{
    int ret = 0;
    for (int i = poz; i; i -= lsb(i))
        ret += aib[i];
    return ret;
}

int query(int st, int dr)
{
    if (st == 0)
        return getSum(dr);
    return getSum(dr) - getSum(st - 1);
}

int main()
{
    cin >> n >> m >> w >> h;
    for (int i = 1; i <= n; i++)
    {
        int x, y;
        cin >> x >> y;
        dr.push_back({y, x});
    }

    for (int i = 1; i <= m; i++)
    {
        int x, y;
        cin >> x >> y;
        oi.push_back({y, x});
    }

    int rez = 0;
    int currDr = 0, currOi = 0, currOi2 = 0;

    // liniile 0...h
    for (int i = 0; i <= h; i++)
    {
        while (currOi < oi.size() && oi[currOi].first == i)
        {
            update(oi[currOi].second, 1);
        }
    }
    while (currDr < dr.size() && dr[currDr].first == 0)
    {
        pair <int, int> da = dr[currDr];
        rez += query(da.second, da.second + w);
        currDr++;
    }

    for (int i = h + 1; i <= 1e6 + 5; i++)
    {
        // bag linia i, scot linia i-h-1
        while (currOi < oi.size() && oi[currOi].first == i)
            update(oi[currOi].second, 1), currOi++;
            
        while (currOi2 < oi.size() && oi[currOi2].first == i - h - 1)
            update(oi[currOi2].second, -1), currOi2++;

        while (currDr < dr.size() && dr[currDr].first == i - h)
        {
            pair <int, int> da = dr[currDr];
            rez += max(0, query(da.second, da.second + w));
            currDr++;
        }
    }

    for (int i = 1e6 + 6; i <= 2e6 + 5; i++)
        while (currDr < dr.size() && dr[currDr].first == i - h)
        {
            pair <int, int> da = dr[currDr];
            rez += max(0, query(da.second, da.second + w));
            currDr++;
        }

    cout << rez << "\n";

    //cout << (sizeof(dr) + sizeof(oi) + sizeof(aib)) / 1000;

    return 0;
}