#include<stdio.h>
int main()
{
	int N,M,B,G;
	int a[102],b[102],c[102],d[102];
	int hang,lie;
	scanf("%d %d %d %d",&N,&M,&B,&G);
	hang=N;
	lie=M;
	for(int i=1;i<=B;i++)
	{
		scanf("%d %d",&a[i],&b[i]);
		if(a[i]!=b[i-1]&&b[i]!=a[i-1])
		hang-=b[i]-a[i]+1;
		else
		hang-=b[i]-a[i];
		printf("\n");
	}
	for(int o=1;o<=G;o++)
	{
		scanf("%d %d",&c[o],&d[o]);
		if(c[o]!=d[o-1]&&d[o]!=c[o-1])
		lie-=d[o]-c[o]+1;
		else
		lie-=d[o]-c[o];
		printf("\n");
	}
	printf("%d",M*N-hang*lie);
	return 0;
}