class A:
    def __init__(self, txt: str):
        self.z: E = None
        self.y: F = None
        self.p: A = None
        self.w: B = None
        self.r: B = None
        self.s: A = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: E = None
        self.s: E = None
        self.t: E = None
        self.z: C = None
        self.v: C = None
        self.x: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.r: A = None
        self.y: C = None
        self.z: A = None
        self.p: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.z: D = None
        self.t: D = None
        self.txt = txt

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

c = A("c")
k = B("k")
b = C("b")
n = D("n")
h = E("h")
f = F("f")
e = C("e")
l = A("l")

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

class B:
    def __init__(self, txt: str):
        self.o: E = None
        self.s: E = None
        self.t: E = None
        self.z: C = None
        self.v: C = None
        self.x: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.r: A = None
        self.y: C = None
        self.z: A = None
        self.p: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.z: D = None
        self.t: D = None
        self.txt = txt

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

c = A("c")
k = B("k")
b = C("b")
n = D("n")
h = E("h")
f = F("f")
e = C("e")
l = A("l")

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