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

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

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

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

i = A("i")
e = B("e")
b = C("b")
h = D("h")
j = A("j")
l = B("l")
a = C("a")
c = D("c")
d = A("d")

i.t = b
i.z = c
e.o = a
e.x = c
e.s = h
b.y = c
h.y = a
h.o = c
h.v = b
j.t = a
j.z = h
l.o = b
l.x = c
l.s = h
a.y = c
c.y = b
c.v = b
c.o = h
d.t = b
d.z = h
assert c.o.o.y.y.txt == "
class A:
    def __init__(self, txt: str):
        self.t: C = None
        self.z: D = None
        self.txt = txt

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

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

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

i = A("i")
e = B("e")
b = C("b")
h = D("h")
j = A("j")
l = B("l")
a = C("a")
c = D("c")
d = A("d")

i.t = b
i.z = c
e.o = a
e.x = c
e.s = h
b.y = c
h.y = a
h.o = c
h.v = b
j.t = a
j.z = h
l.o = b
l.x = c
l.s = h
a.y = c
c.y = b
c.v = b
c.o = h
d.t = b
d.z = h
assert c.o.o.y.y.txt == "c"