class A:
    def __init__(self, txt: str):
        self.u: D = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.z: G = None
        self.r: D = None
        self.t: D = None
        self.p: B = None
        self.q: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.u: E = None
        self.q: A = None
        self.z: B = None
        self.o: E = None
        self.s: C = None
        self.x: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.v: E = None
        self.u: C = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.z: G = None
        self.r: D = None
        self.t: D = None
        self.p: B = None
        self.q: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.u: E = None
        self.q: A = None
        self.z: B = None
        self.o: E = None
        self.s: C = None
        self.x: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.v: E = None
        self.u: C = None
        self.txt = txt

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

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