class A:
    def __init__(self, txt: str):
        self.o: C = None
        self.p: E = None
        self.s: E = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: C = None
        self.u: C = None
        self.t: A = None
        self.p: C = None
        self.z: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.s: F = None
        self.q: D = None
        self.w: B = None
        self.u: D = None
        self.r: D = None
        self.txt = txt

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: C = None
        self.u: C = None
        self.t: A = None
        self.p: C = None
        self.z: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.s: F = None
        self.q: D = None
        self.w: B = None
        self.u: D = None
        self.r: D = None
        self.txt = txt

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

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

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