class A:
    def __init__(self, txt: str):
        self.y: D = None
        self.x: H = None
        self.o: D = None
        self.r: G = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: G = None
        self.t: G = None
        self.p: C = None
        self.r: G = None
        self.s: C = None
        self.y: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: H = None
        self.p: H = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.w: G = None
        self.v: G = None
        self.y: E = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.x: C = None
        self.y: B = None
        self.w: A = None
        self.z: H = None
        self.p: D = None
        self.t: C = None
        self.s: F = None
        self.txt = txt

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

f = A("f")
k = B("k")
d = C("d")
l = D("l")
g = E("g")
h = F("h")
a = G("a")
i = H("i")
j = E("j")
b = C("b")

f.y = l
f.o = l
f.x = i
f.r = a
k.q = h
k.w = a
k.t = a
k.r = a
k.p = b
k.s = b
k.y = j
d.o = i
d.p = i
d.v = k
l.z = i
l.w = a
l.v = a
l.y = g
g.x = i
h.v = a
a.u = g
a.x = b
a.t = b
a.y = k
a.w = f
a.z = i
a.p = l
a.s = h
i.z = d
i.r = a
i.x = l
j.x = i
b.o = i
b.p = i
b.v = k
assert h.v.w.x.txt == "
class A:
    def __init__(self, txt: str):
        self.y: D = None
        self.x: H = None
        self.o: D = None
        self.r: G = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: G = None
        self.t: G = None
        self.p: C = None
        self.r: G = None
        self.s: C = None
        self.y: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: H = None
        self.p: H = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.w: G = None
        self.v: G = None
        self.y: E = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.x: C = None
        self.y: B = None
        self.w: A = None
        self.z: H = None
        self.p: D = None
        self.t: C = None
        self.s: F = None
        self.txt = txt

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

f = A("f")
k = B("k")
d = C("d")
l = D("l")
g = E("g")
h = F("h")
a = G("a")
i = H("i")
j = E("j")
b = C("b")

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