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

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

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.v: A = None
        self.y: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.p: C = None
        self.v: A = None
        self.x: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: F = None
        self.o: B = None
        self.w: C = None
        self.y: F = None
        self.t: D = None
        self.x: F = None
        self.txt = txt

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

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

j.z = a
j.s = b
j.v = i
l.u = j
l.x = h
l.s = h
l.q = i
l.t = c
l.z = b
h.p = b
h.v = j
h.y = i
c.q = a
c.p = h
c.v = i
c.x = i
e.s = b
e.y = b
e.x = b
e.o = a
e.w = h
e.t = c
b.z = e
b.o = e
b.y = j
b.x = c
i.z = a
i.s = b
i.v = j
a.u = i
a.x = h
a.s = h
a.q = j
a.t = c
a.z = b
assert a.u.v.s.y.txt == "
class A:
    def __init__(self, txt: str):
        self.z: B = None
        self.s: F = None
        self.v: A = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.v: A = None
        self.y: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.p: C = None
        self.v: A = None
        self.x: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: F = None
        self.o: B = None
        self.w: C = None
        self.y: F = None
        self.t: D = None
        self.x: F = None
        self.txt = txt

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

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

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