#include <bits/stdc++.h>
using namespace std;

struct vec3 {
    double x, y, z;
    
    vec3 operator-(const vec3& that){
        return vec3{x - that.x, y - that.y, z - that.z};
    }
};

vec3 cross(vec3 a, vec3 b){
    return vec3{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 dist(vec3 A, vec3 B, vec3 C, vec3 P){
    vec3 normal = cross(B - A, C - A);
    
    double a = normal.x;
    double b = normal.y;
    double c = normal.z;
    double d = -(a * A.x + b * A.y + c * A.z);
    
    double res = abs(a * P.x + b * P.y + c * P.z + d) / sqrt(a * a + b * b + c * c);
    return res;
}

int main(){
    int N;
    cin >> N;
    
    vec3 P;
    cin >> P.x >> P.y >> P.z;
    
    vector<vec3> Q(N);
    for(int i=0;i<N;i++){
        cin >> Q[i].x >> Q[i].y >> Q[i].z;
    }
    
    double res = 0;
    for(int i=0;i<N;i++)for(int j=i+1;j<N;j++)for(int k=j+1;k<N;k++){
        res += dist(Q[i], Q[j], Q[k], P);
    }
    
    printf("%.15f\n", res);
    return 0;
}