#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <complex>
using namespace std;
const double EPS = 1e-10;
const double INF = 1e12;
#define EQ(n,m) (abs((n)-(m)) < EPS)
#define X real()
#define Y imag()

typedef complex<double> P;
typedef vector<P> VP;
namespace std{
    bool operator < (const P& a, const P& b){
        return !EQ(a.X,b.X) ? a.X<b.X : a.Y+EPS<b.Y;
    }
    bool operator == (const P& a, const P& b){
        return abs(a-b) < EPS;
    }
}

double dot(P a, P b){
    return (conj(a)*b).X;
}
double cross(P a, P b){
    return (conj(a)*b).Y;
}
int ccw(P a, P b, P c){
    b -= a;
    c -= a;
    if(cross(b,c) > EPS) return +1; //ccw
    if(cross(b,c) < -EPS) return -1; //cw
    if(dot(b,c) < -EPS) return +2; //c-a-b
    if(abs(c)-abs(b) > EPS) return -2; //a-b-c
    return 0; //a-c-b
}

double getarea(const VP &poly){
    double ret = 0;
    for (int i=0; i<(int)poly.size(); i++){ 
        ret += cross(poly[i], poly[(i+1)%poly.size()]);
    }
    return ret*0.5;
}
VP convex(VP v){
    VP ret;
    int n = v.size();
    sort(v.begin(), v.end());
    for(int i=0; i<n; i++){
        while((int)ret.size()>1 && cross(ret.back()-ret[ret.size()-2], v[i]-ret.back()) < EPS){
            ret.pop_back();
        }
        ret.push_back(v[i]);
    }
    int t = ret.size();
    for(int i=n-2; i>=0; i--){
        while((int)ret.size()>t && cross(ret.back()-ret[ret.size()-2], v[i]-ret.back()) < EPS){
            ret.pop_back();
        }
        ret.push_back(v[i]);
    }
    if((int)ret.size() > 1) ret.pop_back();
    return ret;
}

struct Point{
    double x,y,z;
    Point(double x, double y, double z):x(x), y(y), z(z){}
    Point(){}
    Point &operator +=(const Point &a){ x+=a.x; y+=a.y; z+=a.z; return *this; }
    Point &operator -=(const Point &a){ x-=a.x; y-=a.y; z-=a.z; return *this; }
    Point &operator *=(const double &a){ x*=a; y*=a; z*=a; return *this; }
    Point operator +(const Point &a) const{ return Point(x+a.x, y+a.y, z+a.z); }
    Point operator -(const Point &a) const{ return Point(x-a.x, y-a.y, z-a.z); }
    Point operator *(const double &a) const{ return Point(a*x, a*y, a*z); }
    Point operator -() { return Point(-x, -y, -z); }
};
 
double dot(const Point &a, const Point &b){
    return a.x*b.x +a.y*b.y +a.z*b.z;
}
Point cross(const Point &a, const Point &b){
    return Point(a.y*b.z -a.z*b.y, a.z*b.x -a.x*b.z, a.x*b.y -a.y*b.x);
}
double abs(const Point &a){
    return sqrt(dot(a, a));
}
Point unit(const Point &a){
    return a *(1/abs(a));
}
bool operator ==(const Point &a, const Point &b){
    return abs(a-b) < EPS;
}

//2次元に転写して凸包の面積を出す
double convex_area(const vector<Point> &p, Point normal){
    VP p2d;
    Point base = p[1] -p[0];
    p2d.emplace_back(0, 0);
    p2d.emplace_back(abs(base), 0);
    for(int i=2; i<(int)p.size(); i++){
        Point v = p[i] -p[0];
        double theta = acos(dot(base, v)/(abs(base)*abs(v)));
        if(dot(cross(base, v), normal) > 0){
            theta *= -1;
        }
        p2d.push_back(P(abs(v), 0) *P(cos(theta), sin(theta)));
    }
    return getarea(convex(p2d));
}

int main(){
    int n;
    cin >> n;
    vector<Point> p(n);
    for(int i=0; i<n; i++){
        cin >> p[i].x >> p[i].y >> p[i].z;
    }

    bool used[50][50][50];
    memset(used, false, sizeof(used));
    double ans = 0;
    //点を3つ選ぶ
    for(int i=0; i<n; i++){
        for(int j=i+1; j<n; j++){
            for(int k=j+1; k<n; k++){
                if(used[i][j][k]) continue;
                Point normal = cross(p[j]-p[i], p[k]-p[i]);
                if(abs(normal) < EPS) continue;
                //同じ平面上の点を列挙
                vector<int> onplane, nop;
                for(int l=0; l<n; l++){
                    if(l==i || l==j || l==k || abs(dot(normal, p[l] -p[i])) < EPS){
                        onplane.push_back(l);
                    }else{
                        nop.push_back(l);
                    }
                }
                int m = onplane.size();
                for(int s=0; s<m; s++){
                    for(int t=s+1; t<m; t++){
                        for(int u=t+1; u<m; u++){
                            used[onplane[s]][onplane[t]][onplane[u]] = true;
                        }
                    }
                }
                //平面に対してすべて同じ方向にあるかどうか
                int sign = 0;
                for(int s=0; s<(int)nop.size(); s++){
                    double d = dot(normal, p[nop[s]] -p[i]);
                    if((sign==1 && d<0) || (sign==-1 && d>0)){
                        sign = 0;
                        break;
                    }
                    if(d > 0) sign = 1;
                    else sign = -1;
                }
                if(sign != 0){
                    vector<Point> plist;
                    for(int i=0; i<(int)onplane.size(); i++){
                        plist.push_back(p[onplane[i]]);
                    }
                    ans += convex_area(plist, normal);
                }
            }
        }
    }
    cout << fixed << setprecision(10);
    cout << ans << endl;
    return 0;
}


Measured memory_bytes: 3788