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

class B:
    def __init__(self, txt: str):
        self.o: H = None
        self.y: A = None
        self.x: H = None
        self.q: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: J = None
        self.r: J = None
        self.z: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: A = None
        self.p: C = None
        self.z: C = None
        self.y: C = None
        self.o: F = None
        self.u: H = None
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: I = None
        self.u: B = None
        self.v: A = None
        self.s: J = None
        self.q: C = None
        self.r: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.r: J = None
        self.p: D = None
        self.u: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.v: F = None
        self.s: C = None
        self.u: D = None
        self.r: B = None
        self.o: H = None
        self.t: J = None
        self.x: F = None
        self.p: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.q: G = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.o: H = None
        self.y: A = None
        self.x: H = None
        self.q: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: J = None
        self.r: J = None
        self.z: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: A = None
        self.p: C = None
        self.z: C = None
        self.y: C = None
        self.o: F = None
        self.u: H = None
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: I = None
        self.u: B = None
        self.v: A = None
        self.s: J = None
        self.q: C = None
        self.r: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.r: J = None
        self.p: D = None
        self.u: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.v: F = None
        self.s: C = None
        self.u: D = None
        self.r: B = None
        self.o: H = None
        self.t: J = None
        self.x: F = None
        self.p: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.q: G = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: B = None
        self.txt = txt

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

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