n = int(input())
px, py, pz = map(float, input().split())
XYZ = []
for i in range(n):
    x, y, z = map(float, input().split())
    XYZ.append((x, y, z))

def cross(a, b):
    x = a[1]*b[2]-b[1]*a[2]
    y = (-1)*(a[0]*b[2]-b[0]*a[2])
    z = a[0]*b[1]-b[0]*a[1]
    return (x, y, z)

import itertools, math
ans = 0
for ijk in itertools.combinations(range(n), 3):
    qi = XYZ[ijk[0]]
    qj = XYZ[ijk[1]]
    qk = XYZ[ijk[2]]
    v1 = [aj-ai for aj, ai in zip(qj, qi)]
    v2 = [ak-ai for ak, ai in zip(qk, qi)]
    a, b, c = cross(v1, v2)
    d = sum([-v*u for u, v in zip([a, b, c], qi)])
    dist = abs(a*px+b*py+c*pz+d)/math.sqrt(a**2+b**2+c**2)
    ans += dist
print(ans)