#include<bits/stdc++.h>
using namespace std;
const int N =3030;
typedef long long LL;
#define BIG __int128
int n;
LL Ra,Rb;
LL a[N],b[N];
mt19937 rnd(time(0));
int Make(int l,int r)
{
	return rnd()%(r-l+1)+l;
}
void print(BIG x)
{
	if(x>9)print(x/10);
	putchar('0'+x%10);
}
BIG A=0,B=0,C=0;
int state[N];
const int LIM = 50000;
const int K = 1;
int p[N];
void solve()
{
	for(int i=1;i<=n;i++)scanf("%lld %lld",&a[i],&b[i]);
	A=0;B=0;C=0;BIG D=0;
	for(int ip=1;ip<=30;ip++)
	{
		A=0;B=0;C=0;
		for(int i=1;i<=n;i++)p[i]=i;
		shuffle(p+1,p+n+1,rnd);
		int mid=(n/2);
		for(int i=1;i<=n;i++)
		{
			int x=p[i];
			if(i<=mid)state[x]=0,A+=a[x];
			else state[x]=1,B+=b[x];
		}
		C=A*B;D=max(D,C);
		for(int o=1;o<=LIM;o++)
		{
			int x=Make(1,n);
			LL nA=A,nB=B;
			if(state[x]==0)nA-=a[x],nB+=b[x];
			else nA+=a[x],nB-=b[x];
			if(nA*nB>C)
			{
				C=nA*nB;
				A=nA;B=nB;
				D=max(D,C);
				state[x]^=1;
			}
		}
	}
	print(D);
	putchar('\n');
}
int main() 
{
	int T;
	scanf("%d %d %lld %lld",&T,&n,&Ra,&Rb);
	while(T--)
	{
		solve();
	}
	return 0;
}