import math
def cross_v(p1,p2):
	return (p1[1]*p2[2]-p1[2]*p2[1],p1[2]*p2[0]-p1[0]*p2[2],p1[0]*p2[1]-p1[1]*p2[0])
def inner_p(p1,p2):
	return sum(p1[i]*p2[i] for i in xrange(3))
def vec_s(p1,p2):
	return (p1[0]-p2[0],p1[1]-p2[1],p1[2]-p2[2])
def dps(q1,q2,q3):
	n_v = cross_v(vec_s(q2,q1),vec_s(q3,q1))
	return abs(inner_p(vec_s(p,q1),n_v)) / math.sqrt(sum(c**2 for c in n_v))
N = input()
f = lambda x: float(x)
p = map(f,raw_input().split())
q = [map(f,raw_input().split()) for i in xrange(N)]
print "%.10f" % sum([dps(q[i],q[j],q[k]) for i in xrange(N-2) for j in xrange(i+1,N-1) for k in xrange(j+1,N)])