class A:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: A = None
        self.u: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: F = None
        self.p: F = None
        self.u: D = None
        self.x: B = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.z: E = None
        self.u: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.w: C = None
        self.v: C = None
        self.s: F = None
        self.p: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: F = None
        self.r: E = None
        self.p: A = None
        self.v: F = None
        self.s: F = None
        self.u: A = None
        self.txt = txt

e = A("e")
b = B("b")
i = C("i")
k = D("k")
f = E("f")
g = F("g")
l = C("l")
c = A("c")
j = F("j")

e.p = c
e.x = c
e.u = j
b.x = c
b.p = k
i.z = g
i.p = j
i.u = k
i.x = b
i.v = f
k.x = i
k.z = f
k.u = e
f.u = i
f.w = l
f.v = l
f.s = j
f.p = c
g.z = j
g.v = j
g.s = j
g.r = f
g.p = c
g.u = e
l.z = g
l.p = g
l.u = k
l.x = b
l.v = f
c.p = e
c.x = e
c.u = g
j.z = g
j.v = g
j.s = g
j.r = f
j.p = c
j.u = c
assert k.u.p.u.s.v.s.txt == "
class A:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: A = None
        self.u: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: F = None
        self.p: F = None
        self.u: D = None
        self.x: B = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.z: E = None
        self.u: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.w: C = None
        self.v: C = None
        self.s: F = None
        self.p: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: F = None
        self.r: E = None
        self.p: A = None
        self.v: F = None
        self.s: F = None
        self.u: A = None
        self.txt = txt

e = A("e")
b = B("b")
i = C("i")
k = D("k")
f = E("f")
g = F("g")
l = C("l")
c = A("c")
j = F("j")

e.p = c
e.x = c
e.u = j
b.x = c
b.p = k
i.z = g
i.p = j
i.u = k
i.x = b
i.v = f
k.x = i
k.z = f
k.u = e
f.u = i
f.w = l
f.v = l
f.s = j
f.p = c
g.z = j
g.v = j
g.s = j
g.r = f
g.p = c
g.u = e
l.z = g
l.p = g
l.u = k
l.x = b
l.v = f
c.p = e
c.x = e
c.u = g
j.z = g
j.v = g
j.s = g
j.r = f
j.p = c
j.u = c
assert k.u.p.u.s.v.s.txt == "j"