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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.s: B = None
        self.z: B = None
        self.x: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.z: D = None
        self.o: E = None
        self.t: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.w: A = None
        self.z: E = None
        self.t: C = None
        self.s: E = None
        self.p: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: D = None
        self.w: A = None
        self.v: B = None
        self.o: E = None
        self.p: E = None
        self.txt = txt

e = A("e")
f = B("f")
j = C("j")
k = D("k")
b = E("b")
h = F("h")
g = E("g")
i = B("i")
d = A("d")

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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.s: B = None
        self.z: B = None
        self.x: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.z: D = None
        self.o: E = None
        self.t: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.w: A = None
        self.z: E = None
        self.t: C = None
        self.s: E = None
        self.p: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: D = None
        self.w: A = None
        self.v: B = None
        self.o: E = None
        self.p: E = None
        self.txt = txt

e = A("e")
f = B("f")
j = C("j")
k = D("k")
b = E("b")
h = F("h")
g = E("g")
i = B("i")
d = A("d")

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