#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

struct point{
    long long x,y;
};


point operator-(point u,point v){
    return {u.x-v.x,u.y-v.y};
}
long long operator^(point u,point v){
    return u.x*v.y-u.y*v.x;
}
bool cmp(point u,point v){
    return u.x==v.x?u.y<v.y:u.x<v.x;
}
int order(point u,point v){
    if((u^v)>0) return 1;
    if((u^v)==0) return 0;
    return -1;
}

void maxncon(point *u,int size,point *h,int &hsize){
    sort(u+1,u+1+size,cmp);
    h[1]=u[1];
    int top1=1,top2=1;
    for(int i=2;i<=size;i++){
        while(top1>1){
            point begin=h[top1]-h[top1-1];
            point Next=u[i]-h[top1];
            int p=order(begin,Next);
            if(p==1||p==0){
                h[++top1]=u[i];
                break;
            }
            else top1--;
        }
        if(top1==1) h[++top1]=u[i];
    }
    for(int i=size-1;i>=1;i--){
        while(top2>1){
            point begin=h[top1+top2-1]-h[top1+top2-2];
            point Next=u[i]-h[top1+top2-1];
            int p=order(begin,Next);
            if(p==1||p==0) {
                h[++top2+top1-1]=u[i];
                break;
            }
            else top2--;
        }
        if(top2==1) h[++top2+top1-1]=u[i];
    }
    hsize=max(1,top1+top2-2);
    return ;
}
void print(__int128 num) {
    if (num > 9) {
    print(num / 10);
    }
    putchar(num % 10 + '0');
}
void solve() {
    int n,m=0,k=0,p=0;
    cin>>n;
    point a[2*n+10],b[2*n+10],c[2*n+10],d[4*n+10];
    map<pair<int,int>,int>mp;
    for(int i=1;i<=n;i++){
        cin>>a[i].x>>a[i].y;
    }
    maxncon(a,n,b,m);
    if(n==m){
        printf("-1\n");
        return ;
    }
    for(int i=1;i<=m;i++){
        mp[{b[i].x,b[i].y}]=1;
    }
    
    for(int i=1;i<=n;i++){
        if(!mp[{a[i].x,a[i].y}]){
            k++;
            c[k]=a[i];
        }
    }
    maxncon(c,k,d,p);
    // cout<<p<<endl;
    for(int i=1;i<=2*p;i++){
        d[i+p]=d[i];
    }
    b[m+1]=b[1];
    int j=1;
    __int128 ans=0,sum=6e18;
    for(int i=2;i<=m;i++){
        ans+=abs((b[i]-b[1])^(b[i+1]-b[1]));
    }
    for(int i=1;i<=m;i++){
        while(abs((d[j]-b[i])^(d[j]-b[i+1]))>abs((d[j+1]-b[i])^(d[j+1]-b[i+1]))){
            j++;
        }
        sum=min(sum,(__int128)abs((d[j]-b[i])^(d[j]-b[i+1])));
    }
    print(ans-sum);
    printf("\n");
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int t = 1;
    cin >> t;
    while(t -- ) {
        solve();
    }
    
    return 0;
}