Problem: Nowadays all circuses in Berland have a round arena with diameter 13 meters, but in the past things were different.

In Ancient Berland arenas in circuses were shaped as a regular (equiangular) polygon, the size and the number of angles could vary from one circus to another. In each corner of the arena there was a special pillar, and the rope strung between the pillars marked the arena edges.

Recently the scientists from Berland have discovered the remains of the ancient circus arena. They found only three pillars, the others were destroyed by the time.

You are given the coordinates of these three pillars. Find out what is the smallest area that the arena could have.

Input

The input file consists of three lines, each of them contains a pair of numbers –– coordinates of the pillar. Any coordinate doesn't exceed 1000 by absolute value, and is given with at most six digits after decimal point.

Output

Output the smallest possible area of the ancient arena. This number should be accurate to at least 6 digits after the decimal point. It's guaranteed that the number of angles in the optimal polygon is not larger than 100.

Examples

Input

0.000000 0.000000
1.000000 1.000000
0.000000 1.000000


Output

1.00000000

Solution (in PYTHON3):

Solution:
#!/usr/bin/env python3

from math import sin, cos, pi, sqrt

# Number of given points
NUMPOINTS = 3

# Maximum amount of sides of the polygon
MAXSIDES = 100

# Point comparison precision (decimal signs)
PRECISION = 4

# Enable debug logging
DEBUG = False


# Отладочный вывод
def log(arg, highlight=False):
    if not DEBUG:
        return

    if highlight:
        print('\033[4m' + str(arg) + '\033[0m')
    else:
        print(arg)


# Список известных точек (колышков)
p = []

# Point comparison error
epsilon = 10 ** (-1 * PRECISION)
log('Error: {}'.format(epsilon))


# Input all points
log('Source points', True)

for i in range(NUMPOINTS):
    s = [float(n) for n in input().strip().split()]
    p.append((s[0], s[1]))

log(p)


# Нельзя допустить нулевой знаменатель при дальнейших расчётах
log('Permuted points', True)

if p[1][0] == p[0][0]:
    tmp = p[2]
    p[2] = p[1]
    p[1] = tmp

if p[2][0] == p[1][0]:
    tmp = p[2]
    p[2] = p[0]
    p[0] = tmp

log(p)


# Line slope coefficient
log('Line slope coefficients', True)

ma = (p[1][1] - p[0][1]) / (p[1][0] - p[0][0])
mb = (p[2][1] - p[1][1]) / (p[2][0] - p[1][0])

log('ma = {}, mb = {}'.format(ma, mb))


# Circumcircle center
log('Circumcircle center', True)

x = (ma * mb * (p[0][1] - p[2][1]) + mb * (p[0][0] + p[1][0]) - ma * (p[1][0] + p[2][0])) / (2 * (mb - ma))
y = -1 * (x - (p[0][0] + p[1][0]) / 2) / ma + (p[0][1] + p[1][1]) / 2

log('x = {}, y = {}'.format(x, y))


# Offset all points so that circumcircle's center is at (0; 0)
log('Point offset', True)

tmp, p = p, []

for point in tmp:
    p.append((point[0] - x, point[1] - y))

log(p)


# Checl every polygon for matching points
for n in range(3, MAXSIDES + 1):
    log('Number of sides: {}'.format(n), True)

    matched = 1

    d = 2 * pi / n
    sind = sin(d)
    cosd = cos(d)

    log('d = {}, sind = {}, cosd = {}'.format(d, sind, cosd))

    pd = p[0]

    for i in range(1, n):
        pd = (pd[0] * cosd - pd[1] * sind, pd[0] * sind + pd[1] * cosd)

        log('i = {}, p = {}'.format(i, pd))

        for point in p[1:]:
            delta = sqrt((point[0] - pd[0]) ** 2 + (point[1] - pd[1]) ** 2)

            log('\tpoint = {}, delta = {}'.format(point, delta))

            if delta < epsilon:
                matched += 1

    if matched == NUMPOINTS:
        break

# Радиус описанной окружности
radius = sqrt(p[0][0] ** 2 + p[0][1] ** 2)

# Площадь n-стороннего многоугольника с радиусом выше
area = n * (radius ** 2) * sind / 2

print(area)