class A:
    def __init__(self, txt: str):
        self.y: E = None
        self.x: D = None
        self.w: B = None
        self.o: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.u: C = None
        self.t: J = None
        self.w: D = None
        self.s: I = None
        self.v: A = None
        self.r: H = None
        self.o: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: J = None
        self.q: I = None
        self.w: J = None
        self.u: F = None
        self.s: D = None
        self.p: J = None
        self.o: G = None
        self.x: D = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: A = None
        self.p: B = None
        self.v: C = None
        self.y: A = None
        self.w: H = None
        self.x: I = None
        self.u: B = None
        self.r: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: I = None
        self.z: C = None
        self.q: D = None
        self.v: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.o: I = None
        self.r: J = None
        self.z: C = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: E = None
        self.r: B = None
        self.w: J = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: H = None
        self.r: E = None
        self.p: F = None
        self.x: J = None
        self.v: C = None
        self.z: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.o: D = None
        self.q: A = None
        self.txt = txt

c = A("c")
f = B("f")
k = C("k")
a = D("a")
j = E("j")
i = F("i")
d = G("d")
h = H("h")
m = I("m")
l = J("l")

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

class B:
    def __init__(self, txt: str):
        self.u: C = None
        self.t: J = None
        self.w: D = None
        self.s: I = None
        self.v: A = None
        self.r: H = None
        self.o: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: J = None
        self.q: I = None
        self.w: J = None
        self.u: F = None
        self.s: D = None
        self.p: J = None
        self.o: G = None
        self.x: D = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: A = None
        self.p: B = None
        self.v: C = None
        self.y: A = None
        self.w: H = None
        self.x: I = None
        self.u: B = None
        self.r: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: I = None
        self.z: C = None
        self.q: D = None
        self.v: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.o: I = None
        self.r: J = None
        self.z: C = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: E = None
        self.r: B = None
        self.w: J = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: H = None
        self.r: E = None
        self.p: F = None
        self.x: J = None
        self.v: C = None
        self.z: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.o: D = None
        self.q: A = None
        self.txt = txt

c = A("c")
f = B("f")
k = C("k")
a = D("a")
j = E("j")
i = F("i")
d = G("d")
h = H("h")
m = I("m")
l = J("l")

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