class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.r: E = None
        self.w: C = None
        self.y: A = None
        self.p: A = None
        self.q: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: F = None
        self.s: B = None
        self.q: B = None
        self.o: F = None
        self.x: B = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.s: C = None
        self.o: D = None
        self.t: A = None
        self.u: D = None
        self.txt = txt

d = A("d")
j = B("j")
a = C("a")
l = D("l")
b = E("b")
k = F("k")
e = C("e")

d.u = j
j.o = d
j.y = l
a.v = j
a.r = b
a.w = e
a.q = e
a.y = d
a.p = d
l.z = k
l.o = k
l.s = j
l.q = j
l.x = j
b.y = l
b.v = a
b.s = k
b.w = k
b.p = j
k.s = a
k.o = l
k.u = l
k.t = d
e.v = j
e.r = b
e.w = a
e.q = a
e.y = d
e.p = d
assert j.o.u.o.u.y.z.txt == "
class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.r: E = None
        self.w: C = None
        self.y: A = None
        self.p: A = None
        self.q: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: F = None
        self.s: B = None
        self.q: B = None
        self.o: F = None
        self.x: B = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.s: C = None
        self.o: D = None
        self.t: A = None
        self.u: D = None
        self.txt = txt

d = A("d")
j = B("j")
a = C("a")
l = D("l")
b = E("b")
k = F("k")
e = C("e")

d.u = j
j.o = d
j.y = l
a.v = j
a.r = b
a.w = e
a.q = e
a.y = d
a.p = d
l.z = k
l.o = k
l.s = j
l.q = j
l.x = j
b.y = l
b.v = a
b.s = k
b.w = k
b.p = j
k.s = a
k.o = l
k.u = l
k.t = d
e.v = j
e.r = b
e.w = a
e.q = a
e.y = d
e.p = d
assert j.o.u.o.u.y.z.txt == "k"