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

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

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

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

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

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

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

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

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

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

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

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

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

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

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