class A:
    def __init__(self, txt: str):
        self.w: F = None
        self.z: D = None
        self.t: B = None
        self.y: E = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: F = None
        self.s: D = None
        self.q: C = None
        self.v: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: A = None
        self.txt = txt

i = A("i")
c = B("c")
d = C("d")
f = D("f")
a = E("a")
n = F("n")
e = B("e")
l = E("l")
h = C("h")

i.w = n
i.z = f
i.t = e
i.y = a
c.s = n
c.r = n
c.v = h
c.t = f
c.x = i
d.s = f
d.t = i
f.p = i
f.v = e
a.t = n
a.v = n
a.s = f
a.q = h
n.o = i
e.s = n
e.r = n
e.v = h
e.t = f
e.x = i
l.t = n
l.v = n
l.s = f
l.q = h
h.s = f
h.t = i
assert n.o.z.v.v.t.w.o.z.txt == "
class A:
    def __init__(self, txt: str):
        self.w: F = None
        self.z: D = None
        self.t: B = None
        self.y: E = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: F = None
        self.s: D = None
        self.q: C = None
        self.v: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: A = None
        self.txt = txt

i = A("i")
c = B("c")
d = C("d")
f = D("f")
a = E("a")
n = F("n")
e = B("e")
l = E("l")
h = C("h")

i.w = n
i.z = f
i.t = e
i.y = a
c.s = n
c.r = n
c.v = h
c.t = f
c.x = i
d.s = f
d.t = i
f.p = i
f.v = e
a.t = n
a.v = n
a.s = f
a.q = h
n.o = i
e.s = n
e.r = n
e.v = h
e.t = f
e.x = i
l.t = n
l.v = n
l.s = f
l.q = h
h.s = f
h.t = i
assert n.o.z.v.v.t.w.o.z.txt == "f"