#include<bits/stdc++.h>

#define ll long long

#define rep(i,a,b) for(int i=a;i<=b;i++)

using namespace std;

struct Point {

    int x,y;

    Point(){};

    Point(int x,int y):x(x),y(y){}

    Point operator + (const Point &b) const {

        return Point(x+b.x,y+b.y);

    }

    Point operator -(const Point &b) const {

        return Point(x-b.x,y-b.y);

    }

    int operator *(const Point &b) const {

        return x*b.y-y*b.x;

    }

    int len() const {

        return x*x+y*y;

    }

    int operator<(const Point &a) const {

        if((*this)*a>0||(*this)*a==0&&len()<a.len()){

            return 1;

        }

        return 0;

    }

}point;

int n;

Point s[122],p[122];

int dp[122][122];

int jud(int m){

    int ans,i,j,now,k,flag,s;

    memset(dp,0,sizeof dp);

    ans = 0;

    for(i=2;i<=m;i++){

        now = i-1;

        while(now>=1&&p[i]*p[now]==0) now--;

        flag = 0;

        if(now==i-1) flag = 1;

        while(now>=1){

            s = p[now]*p[i];

            k = now-1;

            while(k>=1&&(p[now]-p[i])*(p[k]-p[now])>0) k--;

            if(k>=1) s += dp[now][k];

            if(flag) dp[i][now] = s;

            ans = max(ans,s);

            now = k;

        }

        if(flag==0) continue;

        for(j=1;j<=i-1;j++) dp[i][j] = max(dp[i][j],dp[i][j-1]);

    }

    return ans;

}

int main(){

    int t,i,j,m,ans;

    cin>>t;

    while(t--){

        cin>>n;

        for(i=1;i<=n;i++) cin>>s[i].x>>s[i].y;

        ans = 0;

        for(i=1;i<=n;i++){

            m = 0;

            for(j=1;j<=n;j++){

                if(s[j].y>s[i].y||s[j].y==s[i].y&&s[j].x>=s[i].x){

                    p[++m] = s[j]-s[i];

                }

            }

            sort(p+1,p+1+m);

            ans = max(ans,jud(m));

        }

        printf("%.1f\n",ans/2.0);

    }

    return 0;

}