double x[301],y[301],z[301],p,q,r,s;n,i,j;main(k){for(gets(&k);~scanf("%lf%lf%lf",x+n,y+n,z+n);n++);for(;++i<n;)for(j=i;++j<n;)for(k=j;++k<n;s+=fabs(p*(*x-x[i])+q*(*y-y[i])+r*(*z-z[i]))/sqrt(p*p+q*q+r*r))p=(y[j]-y[i])*(z[k]-z[i])-(z[j]-z[i])*(y[k]-y[i]),q=(z[j]-z[i])*(x[k]-x[i])-(x[j]-x[i])*(z[k]-z[i]),r=(x[j]-x[i])*(y[k]-y[i])-(y[j]-y[i])*(x[k]-x[i]);n=!printf("%f",s);}