#include<bits/stdc++.h>
#define ll long long
using namespace std;
inline int read(){
	int x=0,f=1;char ch=getchar();
	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}
	while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
	return x*f;
}
struct Point{
	int x,y;
	Point(const int &_x=0,const int &_y=0):x(_x),y(_y){}
	inline Point operator +(const Point &o){return Point(x+o.x,y+o.y);}
	inline Point operator -(const Point &o){return Point(x-o.x,y-o.y);}
	inline Point operator *(const int &k){return Point(x*k,y*k);}
};
ll dot(Point a,Point b){return 1ll*a.x*b.x+1ll*a.y*b.y;}
ll det(Point a,Point b){return 1ll*a.x*b.y-1ll*a.y*b.x;}
int st[5005],used[5005];
vector<Point>ConvexHull(vector<Point>poly){
	int top=0,len=(int)poly.size();vector<Point>convex;
	sort(poly.begin(),poly.end(),[](Point x,Point y){
		return tie(x.x,x.y)<tie(y.x,y.y);
	});
	st[++top]=0;
	for(int i=1;i<len;i++){
		while(top>=2&&det(poly[st[top]]-poly[st[top-1]],poly[i]-poly[st[top]])<=0)top--;
		st[++top]=i;
	}
	for(int i=1;i<=top;i++)if(!used[st[i]])convex.push_back(poly[st[i]]),used[st[i]]=1;
	top=0;st[++top]=len-1;
	for(int i=len-2;i>=0;i--){
		while(top>=2&&det(poly[st[top]]-poly[st[top-1]],poly[i]-poly[st[top]])<=0)top--;
		st[++top]=i;
	}
	for(int i=1;i<=top;i++)if(!used[st[i]])convex.push_back(poly[st[i]]),used[st[i]]=1;
	for(int i=0;i<len;i++)used[i]=0;
	return convex;
}
ll GetArea(vector<Point>poly){
	int len=(int)poly.size();
	if(len<=2)return 0;
	ll res=0;
	for(int i=0;i<len;i++)res+=det(poly[i],poly[(i+1)%len]);
	return abs(res);
}
ll RotatingCalipers(vector<Point>poly,vector<Point>p){
	int len=(int)poly.size();
//	for(auto x:poly)printf("%lld %lld\n",x.x,x.y);
	if(len<=2)return 0;
	if(len==3){
		int f0=0,f1=0,f2=0;ll res=0,sum=GetArea(poly);
//		printf("{%lld}\n",sum);
		for(auto x:p){
			if(x.x==poly[0].x&&x.y==poly[0].y){
				if(!f0){f0=1;continue;}
				return sum;
			}
			if(x.x==poly[1].x&&x.y==poly[1].y){
				if(!f1){f1=1;continue;}
				return sum;				
			}
			if(x.x==poly[2].x&&x.y==poly[2].y){
				if(!f2){f2=1;continue;}
				return sum;				
			}
			res=max(res,sum-GetArea({poly[0],poly[1],x}));
			res=max(res,sum-GetArea({poly[1],poly[2],x}));
			res=max(res,sum-GetArea({poly[2],poly[0],x}));	
//			printf("(%lld,%lld){%lld,%lld,%lld}\n",x.x,x.y,GetArea({poly[0],poly[1],x}),GetArea({poly[1],poly[2],x}),GetArea({poly[2],poly[0],x}));		
		}
		return res;
	}
	ll res=0;
	for(int i=0;i<len;i++){
		for(int j=(i+2)%len,a=(i+1)%len,b=j;(j+1)%len!=i;j=(j+1)%len){
			if(b==j)b=(b+1)%len;
			while((a+1)%len!=j&&abs(det(poly[i],poly[a])+det(poly[a],poly[j])+det(poly[j],poly[i]))<=abs(det(poly[i],poly[(a+1)%len])+det(poly[(a+1)%len],poly[j])+det(poly[j],poly[i])))a=(a+1)%len;
			while((b+1)%len!=i&&abs(det(poly[i],poly[b])+det(poly[b],poly[j])+det(poly[j],poly[i]))<=abs(det(poly[i],poly[(b+1)%len])+det(poly[(b+1)%len],poly[j])+det(poly[j],poly[i])))b=(b+1)%len;
			res=max(res,abs(det(poly[i],poly[a])+det(poly[a],poly[j])+det(poly[j],poly[b])+det(poly[b],poly[i])));
		}
	}
	return res;
}
void solve(){
	int n=read();vector<Point>p;
	for(int i=1;i<=n;i++){
		int x=read(),y=read();
		p.push_back(Point(x,y));
	}
	vector<Point>convex=ConvexHull(p);
	ll ans=RotatingCalipers(convex,p);
	if(ans%2==0)printf("%lld\n",ans/2);
	else printf("%lld.5\n",ans/2);
}
signed main(){
	int T=read();
	while(T--){
		solve();
	} 
	return 0;
}