class point(object):
     def __init__(self,x,y):
          self.x = x
          self.y = y

class line(object):
     def __init__(self,A,B,C):
          self.A = A
          self.B = B
          self.C = C
def dist(a, b):
    return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y))

def dist_line(p, l):
    return abs(l.A * p.x + l.B * p.y + l.C) / (sqrt(l.A * l.A + l.B * l.B))

def make_point(x, y):
    return point(x, y)

def make_line_byPoint(a, b):


    A = a.y - b.y
    B = b.x - a.x
    C = a.x * b.y -   b.x * a.y

    return line(A, B, C)

def intersect(a, b, lin):
    kek = b
    kek.x -= a.x
    kek.y -= a.y
    l = 0.0
    r = 1.0
    for i in range(1000):
        m1 = l + (r - l) / 3
        m2 = r - (r - l) / 3
        d1 = dist_line(make_point(a.x + kek.x * m1, a.y + kek.y * m1), lin)
        d2 = dist_line(make_point(a.x + kek.x * m2, a.y + kek.y * m2), lin)
        if (d1 > d2):
            l = m1
        else:
            r = m2
    return make_point(a.x + kek.x * l, a.y + kek.y * l)

def sq(a, siz):
    res = 0
    j
    for i in range(siz):
        if (i == a.size() - 1):
            j = 0
        else:
            j = i + 1
        res += (a[i].x - a[j].x) * (a[i].y + a[j].y)
    return abs(res) / 2.0

lines = []
ans = 0.0
def kek(ind, cur, siz):
    if (ind == len(lines)):
        ans = max(ans, sq(cur))
        return
    bubs = []
    for i in range(siz):
        b = intersect(cur[i], cur[(i + 1) % siz], lines[ind])
        if (dist_line(b, lines[ind]) > eps):
            continue
        if (bubs.size() == 0):
            bubs.append({i, b})
            continue
        if (dist(bubs.back().ss, b) > eps):
            bubs.pb({i, b})
    if (bubs.size() == 0):
        kek(ind + 1, cur, siz)
        return
    if (bubs.size() == 1):
        #cout << "on line you f** idiot";
        kek(ind + 1, cur)
        exit(0)

    if (bubs.size() != 2):
        print("something wrong....")
        while (1):
             a = 0
        # если сюда зайдет, то получим tl из-за бесконечного цикла


    i1 = bubs[0].ff
    i2 = bubs[1].ff
    a1
    siz1 = 0
    a1.append(bubs[0].ss)
    siz1 += 1
    for i in range(i1 + 1, i2 + 1):
        a1.append(cur[i])
        siz1 += 1
    a1.append(bubs[1].ss)
    siz1 += 1
    kek(ind + 1, a1)
    a2

    siz2 = 0
    siz2 += 1
    a2.append(bubs[1].ss)
    for i in range(i2 + 1, siz):
         a2.append(cur[i])
         siz2 += 1
    for i in range(0, i1 + 1):
         a2.append(cur[i])
         siz2 += 1
    siz2 += 1
    a2.append(bubs[0].ss)
    kek(ind + 1, a2, siz2)


eps = 0.0000000001

#inp = eval(input())

inp = [((50, 32), (-13, 43)), ((23, -34), (80, 55))]
for i in range(len(inp)):
    p1 = make_point(inp[i][0][0], inp[i][0][1])
    p2 = make_point(inp[i][1][0], inp[i][1][1])
    lines.append(make_line_byPoint(p1, p2))

beg = []
beg.append(make_point(-50, -50))
beg.append(make_point(-50, 50))
beg.append(make_point(50, 50))
beg.append(make_point(50, -50))
kek(0, beg, 4)
print(ans)