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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.s: A = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.z: B = None
        self.p: B = None
        self.v: B = None
        self.o: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.s: A = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.z: B = None
        self.p: B = None
        self.v: B = None
        self.o: B = None
        self.txt = txt

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

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