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

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

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

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

class E:
    def __init__(self, txt: str):
        self.q: I = None
        self.v: I = None
        self.o: A = None
        self.r: F = None
        self.x: C = None
        self.w: B = None
        self.u: A = None
        self.p: C = None
        self.t: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.o: B = None
        self.p: H = None
        self.t: C = None
        self.r: E = None
        self.q: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: I = None
        self.x: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: F = None
        self.y: F = None
        self.o: B = None
        self.s: H = None
        self.t: G = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.q: I = None
        self.v: I = None
        self.o: A = None
        self.r: F = None
        self.x: C = None
        self.w: B = None
        self.u: A = None
        self.p: C = None
        self.t: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.o: B = None
        self.p: H = None
        self.t: C = None
        self.r: E = None
        self.q: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: I = None
        self.x: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: F = None
        self.y: F = None
        self.o: B = None
        self.s: H = None
        self.t: G = None
        self.txt = txt

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

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