class A:
    def __init__(self, txt: str):
        self.r: E = None
        self.u: H = None
        self.z: E = None
        self.o: C = None
        self.v: H = None
        self.q: C = None
        self.t: D = None
        self.p: J = None
        self.s: H = None
        self.x: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.t: G = None
        self.o: H = None
        self.p: J = None
        self.u: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: J = None
        self.u: J = None
        self.t: A = None
        self.x: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: J = None
        self.w: I = None
        self.s: C = None
        self.v: I = None
        self.p: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.r: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: A = None
        self.r: H = None
        self.x: F = None
        self.s: A = None
        self.y: B = None
        self.u: E = None
        self.z: G = None
        self.p: D = None
        self.o: G = None
        self.q: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: C = None
        self.z: A = None
        self.r: B = None
        self.s: H = None
        self.x: G = None
        self.t: B = None
        self.v: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.t: G = None
        self.o: H = None
        self.p: J = None
        self.u: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: J = None
        self.u: J = None
        self.t: A = None
        self.x: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: J = None
        self.w: I = None
        self.s: C = None
        self.v: I = None
        self.p: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.r: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: A = None
        self.r: H = None
        self.x: F = None
        self.s: A = None
        self.y: B = None
        self.u: E = None
        self.z: G = None
        self.p: D = None
        self.o: G = None
        self.q: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: C = None
        self.z: A = None
        self.r: B = None
        self.s: H = None
        self.x: G = None
        self.t: B = None
        self.v: A = None
        self.txt = txt

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

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