#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
//#include <array>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

LD Len(vector<LD> p,vector<LD> q1,vector<LD> q2,vector<LD> q3){
	LD ans=0;
	vector<LD> L0(3),E1(3),E2(3),G(3);
	LD e3;
	rep(i,3){
		L0[i] = p[i] -q1[i];
		E1[i] = q2[i]-q1[i];
		E2[i] = q3[i]-q1[i];
	}
	
	rep(i,3){
		G[i] = E1[(i+1)%3]*E2[(i+2)%3]-E1[(3+i-1)%3]*E2[(3+i-2)%3];
	}
	e3 = sqrt(G[0]*G[0]+G[1]*G[1]+G[2]*G[2]);
	rep(i,3){
		ans += L0[i]*G[i];
	}
	ans /= e3;
	return ans>=0?ans:-ans;
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    cout << setprecision(16);//
	
	int N;
	cin>>N;
	vector<LD> p(3);
	vector< vector<LD>> q(300,vector<LD>(3));
	cin>>p[0]>>p[1]>>p[2];
	rep(i,N){
		cin>>q[i][0]>>q[i][1]>>q[i][2];
	}
	LD ans = 0;
	for(int i=0;i<N-2;++i){
		for(int j=i+1;j<N-1;++j){
			for(int k=j+1;k<N;++k){
				ans += Len(p,q[i],q[j],q[k]);
			}
		}
	}
	P(ans);
	return 0;
}