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

class B:
    def __init__(self, txt: str):
        self.w: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: C = None
        self.t: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: D = None
        self.x: A = None
        self.o: D = None
        self.v: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: A = None
        self.w: A = None
        self.v: F = None
        self.z: D = None
        self.txt = txt

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

e.x = j
b.w = a
n.o = a
n.u = k
a.v = k
a.t = k
a.y = n
k.r = a
k.x = e
k.o = j
k.v = b
f.r = e
f.w = e
f.v = l
f.z = a
j.v = k
j.t = k
j.y = n
l.r = e
l.w = e
l.v = f
l.z = a
assert e.x.t.o.t.v.w.t.txt == "
class A:
    def __init__(self, txt: str):
        self.x: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: C = None
        self.t: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: D = None
        self.x: A = None
        self.o: D = None
        self.v: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: A = None
        self.w: A = None
        self.v: F = None
        self.z: D = None
        self.txt = txt

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

e.x = j
b.w = a
n.o = a
n.u = k
a.v = k
a.t = k
a.y = n
k.r = a
k.x = e
k.o = j
k.v = b
f.r = e
f.w = e
f.v = l
f.z = a
j.v = k
j.t = k
j.y = n
l.r = e
l.w = e
l.v = f
l.z = a
assert e.x.t.o.t.v.w.t.txt == "k"