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

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};


class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if (sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if (vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if (vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while (*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};


InParser fi("ograzi.in");
OutParser fo("ograzi.out");

const int NMAX = 1e6 + 10;

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

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

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

int getSum(int poz)
{
    int ret = 0;
    for (int i = poz; i > 0; 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()
{
    fi >> n >> m >> w >> h;

    for (int i = 1; i <= n; i++)
    {
        int x, y;
        fi >> x >> y;
        x++; y++;
        dr.push_back({y, x});

        maxx = max(maxx, x);
        maxy = max(maxy, y);
    }

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

        maxx = max(maxx, x);
        maxy = max(maxy, y);
    }

    sort(dr.begin(), dr.end());
    sort(oi.begin(), oi.end());

    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 <= maxy + h + 1; 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 = maxy + 1; i <= maxy + h + 1; 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++;
        }*/

    fo << rez;

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

    return 0;
}