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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: B = None
        self.z: D = None
        self.o: E = None
        self.q: F = None
        self.txt = txt

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: B = None
        self.z: D = None
        self.o: E = None
        self.q: F = None
        self.txt = txt

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

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