#include<bits/stdc++.h>
#define ll long long
#define i28 __int128
#define pii pair<ll,ll>
#define fi first
#define se second
#define pb push_back
#define mp make_pair
using namespace std;
int n;
struct Node{ll a,b;}c[3030];
bool operator<(Node a,Node b){
	return ((i28)a.a*(i28)b.b<(i28)a.b*(i28)b.a);
}
void solve(){
	ll sa=0,sb=0;
	for(int i=1;i<=n;++i)scanf("%lld%lld",&c[i].a,&c[i].b),sa+=c[i].a;
	sort(c+1,c+n+1);i28 ans=0;
	for(int i=1;i<=n;++i)sa-=c[i].a,sb+=c[i].b,ans=max(ans,(i28)(sa)*(i28)(sb));
    stack<char>stk;while(stk.size())stk.pop();
    while(ans)stk.push((char)(ans%(i28)(10)+'0')),ans/=(i28)(10);
    while(stk.size())putchar(stk.top()),stk.pop();
    puts("");
}
int main(){
	int t;ll ta,tb;
	cin>>t>>n>>ta>>tb;
	while(t--)solve();
	return 0;
}