#include<bits/stdc++.h>
#define Start cin.tie(0), cout.tie(0), ios::sync_with_stdio(false)
#define PII pair<int,int> 
#define x first
#define y second
#define ull unsigned long long
#define ll long long
using namespace std;

struct edge
{
	int x,y,z;
	bool operator < (const edge &i)	const
	{
		return(x == i.x ? (y == i.y ? z < i.z : y < i.z) : x < i.x);
	}
};

const int M = 1000000007;
const int N = 1e5 + 10;

void func(void);

signed main(void)
{
	Start;
	int _ ; cin >> _;
	while(_--)	func();
	return 0;
}

void func(void)
{
	int n,m,x,y,ans = 0;
	cin >> n >> m >> x >> y;
	vector<PII> a(x);
	vector<PII> b(y);
	for(auto &i : a)	cin >> i.x >> i.y;
	for(auto &i : b)	cin >> i.x >> i.y;
	sort(a.begin(),a.end());
	sort(b.begin(),b.end());
	for(int i=0;i<x;++i)
	{
		for(int j=0;j<y;++j)
		{
			int res = 0;
			if(a[i].y < b[j].x || a[i].x > b[j].y)	continue;
			res += min(a[i].y,b[j].y) - max(a[i].x,b[j].x) + 1;
			ans += (res >= m ? res-m+1 : 0);
		}
	}
	
	cout << ans << '\n';
}