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

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.u: A = None
        self.w: G = None
        self.p: H = None
        self.t: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: A = None
        self.q: H = None
        self.r: G = None
        self.z: I = None
        self.p: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.z: G = None
        self.q: E = None
        self.t: A = None
        self.u: J = None
        self.r: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.p: F = None
        self.y: D = None
        self.o: F = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: I = None
        self.y: H = None
        self.z: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: J = None
        self.s: E = None
        self.y: F = None
        self.x: D = None
        self.r: A = None
        self.w: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: J = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.o: I = None
        self.v: B = None
        self.z: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.u: A = None
        self.w: G = None
        self.p: H = None
        self.t: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: A = None
        self.q: H = None
        self.r: G = None
        self.z: I = None
        self.p: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.z: G = None
        self.q: E = None
        self.t: A = None
        self.u: J = None
        self.r: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.p: F = None
        self.y: D = None
        self.o: F = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: I = None
        self.y: H = None
        self.z: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: J = None
        self.s: E = None
        self.y: F = None
        self.x: D = None
        self.r: A = None
        self.w: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: J = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.o: I = None
        self.v: B = None
        self.z: B = None
        self.txt = txt

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

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