class A:
    def __init__(self, txt: str):
        self.z: B = None
        self.x: G = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.o: H = None
        self.p: E = None
        self.z: H = None
        self.u: F = None
        self.s: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: G = None
        self.q: A = None
        self.x: D = None
        self.s: G = None
        self.y: F = None
        self.w: I = None
        self.z: A = None
        self.u: G = None
        self.o: B = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.y: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.o: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: G = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.o: H = None
        self.p: E = None
        self.z: H = None
        self.u: F = None
        self.s: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: G = None
        self.q: A = None
        self.x: D = None
        self.s: G = None
        self.y: F = None
        self.w: I = None
        self.z: A = None
        self.u: G = None
        self.o: B = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.y: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.o: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: G = None
        self.txt = txt

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

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

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