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

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: F = None
        self.w: G = None
        self.t: F = None
        self.z: A = None
        self.q: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: B = None
        self.p: D = None
        self.txt = txt

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: F = None
        self.w: G = None
        self.t: F = None
        self.z: A = None
        self.q: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: B = None
        self.p: D = None
        self.txt = txt

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

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

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