#include<bits/stdc++.h>
#define ll long long
#define LL __int128
using namespace std;
const int MAXN=3005;
mt19937 rnd(time(0));
int n,id[MAXN];
ll a[MAXN],b[MAXN];
bool s[MAXN];
void solve() {
	for(int i=1;i<=n;++i) cin>>a[i]>>b[i],id[i]=i;
	LL Z=0;
	for(int o=30;o;--o) {
		shuffle(id+1,id+n+1,rnd);
		LL A=0,B=0;
		for(int i=1;i<=n/2;++i) s[i]=0,A+=a[i];
		for(int i=n;i>n/2;--i) s[i]=1,B+=b[i];
		LL X=A*B;
		for(int q=60000;q;--q) {
			int x=rnd()%n+1;
			if(s[x]) {
				if(X<=(A+a[x])*(B-b[x])) s[x]^=1,A+=a[x],B-=b[x],X=A*B;
			} else {
				if(X<=(A-a[x])*(B+b[x])) s[x]^=1,A-=a[x],B+=b[x],X=A*B;
			}
		}
		Z=max(Z,X);
	}
	string z;
	while(Z) z+=Z%10+'0',Z/=10;
	reverse(z.begin(),z.end());
	cout<<z<<"\n";
}
signed main() {
	ios::sync_with_stdio(false);
	int T; ll A,B; cin>>T>>n>>A>>B;
	while(T--) solve();
	return 0;
}