#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
#include<cmath>
#define ll long long
using namespace std;
int T,n,m,a,b;
int main()
{
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d%d%d",&n,&m,&a,&b);
        int Ans=min(n-1,min(m-b,a-1));
        if(a!=b)
        {
            int L=abs(b-a)+1;
            if(n<L)swap(n,L);
            if((n-L)&1)++n;
            Ans=min(Ans,max(0,L+(n-L)/2-2));
        }
        else Ans=min(Ans,(n-1)/2);
        printf("%lld\n",1ll*Ans*Ans);
    }
    return 0;
}