#include <iostream>
using namespace std;

const int MAXF = 100;
const int ICONROW = 15;
const int ICONCOL = 9;

int rowVals[MAXF+1];
int colVals[MAXF+1];
int nrows, ncols;

int grid[MAXF][MAXF];
int wspace[MAXF][MAXF];

struct pos
{
	int r, c;
} dfiles[MAXF], sfiles[MAXF];

void insert(int val, int list[], int& n)
{
	int j=0;
	while (j < n) {
		if (list[j] < val)
			j++;
		else if (list[j] == val)
			return;
		else
			break;
	}
	int tmp = list[j];
	list[j] = val;
	while (j < n) {
		j++;
		int tmp2 = list[j];
		list[j] = tmp;
		tmp = tmp2;
	}
	n++;
}

void insertInGrid(pos p[], int npos, int val)
{
	for(int k=0; k<npos; k++) {
		int i=0, j=0;
		while (rowVals[i] != p[k].r)
			i++;
		while (colVals[j] != p[k].c)
			j++;
		grid[i][j] = val;		// assumes no two files in same position
	}
}

int calcMoves(int startr, int startc, int ndel)
//
// calculate min number of moves for all rects with upper left at startr,startc
//
{
	for(int i=startr; i<nrows; i++)
		for(int j=startc; j<ncols; j++)
			wspace[i][j] = 0;
	wspace[startr][startc] = ndel + grid[startr][startc];
	int minMoves = wspace[startr][startc];
	for(int i=startr+1; i<nrows; i++) {
		int val = wspace[i-1][startc] + grid[i][startc];
		if (val < minMoves)
			minMoves = val;
		wspace[i][startc] = val;
	}
	for(int j=startc+1; j<ncols; j++) {
		int val = wspace[startr][j-1] + grid[startr][j];
		if (val < minMoves)
			minMoves = val;
		wspace[startr][j] = val;
	}
	for(int i=startr+1; i<nrows; i++) {
		for(int j=startc+1; j<ncols; j++) {
			int val = wspace[i-1][j] + wspace[i][j-1] - wspace[i-1][j-1] + grid[i][j];
			if (val < minMoves)
				minMoves = val;
			wspace[i][j] = val;
		}
	}
/*
cout << "Workspace " << startr << ',' << startc << endl;
for(int i=startr; i<nrows; i++) {
for(int j=startc; j<ncols; j++) {
cout << wspace[i][j] << ' ';
}
cout << endl;
}
/**/
	return minMoves;
}

int main()
{
	int maxr, maxc, ndel, nsav,bobs_adjustment=0;
		cin >> maxr >> maxc >> ndel >> nsav;
		nrows = ncols = 0;
		for(int i=0; i<ndel; i++) {
			cin >> dfiles[i].r >> dfiles[i].c;
if (dfiles[i].r > maxr - 8 || dfiles[i].c > maxc - 4) {
  i--;
  ndel--;
  bobs_adjustment++;
  continue;
}
			insert(dfiles[i].r, rowVals, nrows);
			insert(dfiles[i].c, colVals, ncols);
		}
		for(int i=0; i<nsav; i++) {
			cin >> sfiles[i].r >> sfiles[i].c;
			insert(sfiles[i].r, rowVals, nrows);
			insert(sfiles[i].c, colVals, ncols);
		}
/*
for(int i=0; i<nrows; i++)
cout << rowVals[i] << ',';
cout << endl;
for(int i=0; i<ncols; i++)
cout << colVals[i] << ',';
cout << endl;
/**/
		for(int i=0; i<nrows; i++)
			for(int j=0; j<ncols; j++)
				grid[i][j] = 0;
		insertInGrid(dfiles, ndel, -1);
		insertInGrid(sfiles, nsav, 1);
/*
for(int i=0; i<nrows; i++){
for(int j=0; j<ncols; j++)
cout << grid[i][j] << ' ';
cout << endl;
}
/**/
											// now go through all rects
		int minMoves = ndel+nsav;
		for(int i=0; i<nrows; i++) {
			for(int j=0; j<ncols; j++) {
				int moves = calcMoves(i, j, ndel);
				if (moves < minMoves)
					minMoves = moves;
			}
		}
		cout << minMoves+bobs_adjustment << endl;

return 0;
}