class A:
    def __init__(self, txt: str):
        self.t: I = None
        self.w: B = None
        self.u: D = None
        self.o: I = None
        self.s: F = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: G = None
        self.s: B = None
        self.v: G = None
        self.r: I = None
        self.y: E = None
        self.z: I = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: D = None
        self.y: G = None
        self.p: B = None
        self.o: C = None
        self.r: F = None
        self.v: E = None
        self.q: F = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.q: H = None
        self.w: H = None
        self.s: G = None
        self.o: E = None
        self.p: E = None
        self.z: E = None
        self.x: A = None
        self.txt = txt

n = A("n")
b = B("b")
f = C("f")
e = D("e")
d = E("d")
k = F("k")
h = G("h")
i = H("i")
j = I("j")

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: G = None
        self.s: B = None
        self.v: G = None
        self.r: I = None
        self.y: E = None
        self.z: I = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: D = None
        self.y: G = None
        self.p: B = None
        self.o: C = None
        self.r: F = None
        self.v: E = None
        self.q: F = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.q: H = None
        self.w: H = None
        self.s: G = None
        self.o: E = None
        self.p: E = None
        self.z: E = None
        self.x: A = None
        self.txt = txt

n = A("n")
b = B("b")
f = C("f")
e = D("e")
d = E("d")
k = F("k")
h = G("h")
i = H("i")
j = I("j")

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