double area(vector<int>a, vector<int> b, vector<int> c)
// cout<< a[0] <<a[1]<<endl;
// cout<<b[0]<<b[1]<<endl;
//cout<< c[0]<<c[1]<<endl;
lab=sqrt((a[0]-b[0])*(a[0]-b[0]) + (a[1]-b[1])*(a[1]-b[1]));
lbc=sqrt((c[0]-b[0])*(c[0]-b[0]) + (c[1]-b[1])*(c[1]-b[1]));
lac=sqrt((a[0]-c[0])*(a[0]-c[0]) + (a[1]-c[1])*(a[1]-c[1]));
// cout<< lab << ", "<<lbc << ", "<<lac <<endl;
double s=(lab+lbc+lac)/2;
return sqrt(s*(s-lab)*(s-lbc)*(s-lac));
double largestTriangleArea(vector<vector<int>>& points) {
for(int i=0;i<points.size();i++)
for(int j=i+1;j<points.size();j++)
for(int k=j+1;k<points.size();k++)
sum=max(sum, area(points[i], points[j], points[k]));