class A:
    def __init__(self, txt: str):
        self.u: D = None
        self.t: E = None
        self.w: D = None
        self.v: D = None
        self.p: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: B = None
        self.r: F = None
        self.t: B = None
        self.q: B = None
        self.o: C = None
        self.x: C = None
        self.txt = txt

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

e.u = j
e.w = j
e.v = j
e.t = k
e.p = i
a.r = c
i.p = c
j.v = e
j.t = b
b.x = j
b.u = j
b.o = i
b.q = e
f.w = a
f.t = a
f.q = a
f.r = c
f.o = i
f.x = i
k.x = j
k.u = j
k.o = i
k.q = e
c.w = a
c.t = a
c.q = a
c.r = f
c.o = i
c.x = i
assert b.q.t.x.t.x.txt == "
class A:
    def __init__(self, txt: str):
        self.u: D = None
        self.t: E = None
        self.w: D = None
        self.v: D = None
        self.p: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: B = None
        self.r: F = None
        self.t: B = None
        self.q: B = None
        self.o: C = None
        self.x: C = None
        self.txt = txt

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

e.u = j
e.w = j
e.v = j
e.t = k
e.p = i
a.r = c
i.p = c
j.v = e
j.t = b
b.x = j
b.u = j
b.o = i
b.q = e
f.w = a
f.t = a
f.q = a
f.r = c
f.o = i
f.x = i
k.x = j
k.u = j
k.o = i
k.q = e
c.w = a
c.t = a
c.q = a
c.r = f
c.o = i
c.x = i
assert b.q.t.x.t.x.txt == "j"