#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
#define PR 1e-8
#define N 310
struct TPoint
{
	double x,y,z;
	TPoint(){}
	TPoint(double _x,double _y,double _z):x(_x),y(_y),z(_z){}
	TPoint operator-(const TPoint p) {return TPoint(x-p.x,y-p.y,z-p.z);}
	TPoint operator*(const TPoint p) {return TPoint(y*p.z-z*p.y,z*p.x-x*p.z,x*p.y-y*p.x);}//????§?
	double operator^(const TPoint p) {return x*p.x+y*p.y+z*p.z;}//????§?
};
struct fac//
{
	int a,b,c;//??????????????¢????????????????????????
	bool ok;//??\??¢?????????????????????????????¢
};
struct T3dhull
{
	int n;//????§??????°
	TPoint ply[N];//????§????
	int trianglecnt;//?????????????§???¢??°
	fac tri[N];//??????????§???¢
	int vis[N][N];//???i??°???j????±????????????¢
	double dist(TPoint a){return sqrt(a.x*a.x+a.y*a.y+a.z*a.z);}//????????????
	double area(TPoint a,TPoint b,TPoint c){return dist((b-a)*(c-a));}//????§???¢??¢?§?*2
	double volume(TPoint a,TPoint b,TPoint c,TPoint d){return (b-a)*(c-a)^(d-a);}//?????¢?????????????§?*6
	double ptoplane(TPoint &p,fac &f)//??£????????¨??¢??????
	{
		TPoint m=ply[f.b]-ply[f.a],n=ply[f.c]-ply[f.a],t=p-ply[f.a];
		return (m*n)^t;
	}
	void deal(int p,int a,int b)
	{
		int f=vis[a][b];//???????????¢(cnt)??±???(ab)?????£?????¢
		fac add;
		if(tri[f].ok)
		{
			if((ptoplane(ply[p],tri[f]))>PR) dfs(p,f);//??????p???????????°??\??¢f????????§?????±?????¢?´¢f???3???????????\?????´??°??°???????????¢
			else//????????????p???????????°cnt??¢???????????°f??¢??????p??????a???b???????????????????§???¢???
			{
				add.a=b,add.b=a,add.c=p,add.ok=1;
				vis[p][b]=vis[a][p]=vis[b][a]=trianglecnt;
				tri[trianglecnt++]=add;
			}
		}
	}
	void dfs(int p,int cnt)//??´?????????????????????p??¨???????????´??°??????
	{
		tri[cnt].ok=0;//????????¢??????????????????????????¨??´??§??????????????¢

		//?????¢??????????????\(???b,???a)?????\?????¨deal()????????????????????¢(cnt)??±???(ab)?????£?????¢????????????????????´??¢(cnt)?????????3?????¢(?????¬???????????¢?????±??????????????????????????????(1)???????????????(????????¶???)?????¢130???312,?????¬??±???13?????????????????????13,??????????????????31)       

		deal(p,tri[cnt].b,tri[cnt].a);
		deal(p,tri[cnt].c,tri[cnt].b);
		deal(p,tri[cnt].a,tri[cnt].c);
	}
	bool same(int s,int e)//??????????????¢?????????????????¢
	{
		TPoint a=ply[tri[s].a],b=ply[tri[s].b],c=ply[tri[s].c];
		return fabs(volume(a,b,c,ply[tri[e].a]))<PR
			&&fabs(volume(a,b,c,ply[tri[e].b]))<PR
			&&fabs(volume(a,b,c,ply[tri[e].c]))<PR;
	}
	void construct()//????????????
	{
		int i,j;
		trianglecnt=0;
		if(n<4) return ;
		bool tmp=true;
		for(i=1;i<n;i++)//??????????????±???
		{
			if((dist(ply[0]-ply[i]))>PR)
			{
				swap(ply[1],ply[i]); tmp=false; break;
			}
		}
		if(tmp) return;
		tmp=true;
		for(i=2;i<n;i++)//??????????????±???
		{
			if((dist((ply[0]-ply[1])*(ply[1]-ply[i])))>PR)
			{
				swap(ply[2],ply[i]); tmp=false; break;
			}
		}
		if(tmp) return ;
		tmp=true;
		for(i=3;i<n;i++)//??????????????±??¢
		{
			if(fabs((ply[0]-ply[1])*(ply[1]-ply[2])^(ply[0]-ply[i]))>PR)
			{
				swap(ply[3],ply[i]); tmp=false; break;
			}
		}
		if(tmp) return ;
		fac add;
		for(i=0;i<4;i++)//??????????§??????¢???(4?????????ply[0],ply[1],ply[2],ply[3])
		{
			add.a=(i+1)%4,add.b=(i+2)%4,add.c=(i+3)%4,add.ok=1;
			if((ptoplane(ply[i],add))>0) swap(add.b,add.c);//???????????¶???????????????????????????????????°??????????????°???
			vis[add.a][add.b]=vis[add.b][add.c]=vis[add.c][add.a]=trianglecnt;//????????????????????????
			tri[trianglecnt++]=add;
		}
		for(i=4;i<n;i++)//????????´??°??????
		{
			for(j=0;j<trianglecnt;j++)//??????????????????????????¨??????3??´???????????????(i??¨????????????,j??¨???????????¢)
			{
				if(tri[j].ok&&(ptoplane(ply[i],tri[j]))>PR)//?????????????????¢??????????????????????????????????????°????????¢
				{
					dfs(i,j); break;//???????????°????????¢?????´??°???????????¢(????????????????????¢??´??°????????¢)??????????????´??°?????????break????????????

				}
			}
		}
		int cnt=trianglecnt;//????????¢????????????tri[i].ok=0????????¬?±????????§???????????????\????????¨??´??§????????????????????????????????\?????¢????????£???????????¨???????????????????±??????????
		trianglecnt=0;
		for(i=0;i<cnt;i++)
		{
			if(tri[i].ok)
				tri[trianglecnt++]=tri[i];
		}
	}
	double area()//??¨??¢?§?
	{
		double ret=0;
		for(int i=0;i<trianglecnt;i++)
			ret+=area(ply[tri[i].a],ply[tri[i].b],ply[tri[i].c]);
		return ret/2;
	}
	double volume()//????§?
	{
		TPoint p(0,0,0);
		double ret=0;
		for(int i=0;i<trianglecnt;i++)
			ret+=volume(p,ply[tri[i].a],ply[tri[i].b],ply[tri[i].c]);
		return fabs(ret/6);
	}
	int facetri() {return trianglecnt;}//??¨??¢????§???¢??°
	int facepolygon()//??¨??¢????????¢??°
	{
		int ans=0,i,j,k;
		for(i=0;i<trianglecnt;i++)
		{
			for(j=0,k=1;j<i;j++)
			{
				if(same(i,j)) {k=0;break;}
			}
			ans+=k;
		}
		return ans;
	}

}hull;
int main()
{
	while(~scanf("%d",&hull.n))
	{
		int i;
		for(i=0;i<hull.n;i++)
			scanf("%lf%lf%lf",&hull.ply[i].x,&hull.ply[i].y,&hull.ply[i].z);
		hull.construct();
		printf("%.3f\n",hull.area());
	}
	return 0;
}

Measured memory_bytes: 1156