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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.w: B = None
        self.s: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: G = None
        self.u: D = None
        self.w: E = None
        self.p: A = None
        self.o: C = None
        self.txt = txt

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

e = A("e")
i = B("i")
f = C("f")
n = D("n")
b = E("b")
k = F("k")
m = G("m")
d = G("d")
a = A("a")

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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.w: B = None
        self.s: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: G = None
        self.u: D = None
        self.w: E = None
        self.p: A = None
        self.o: C = None
        self.txt = txt

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

e = A("e")
i = B("i")
f = C("f")
n = D("n")
b = E("b")
k = F("k")
m = G("m")
d = G("d")
a = A("a")

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