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

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

class C:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: D = None
        self.o: A = None
        self.u: B = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: C = None
        self.x: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: D = None
        self.s: A = None
        self.w: A = None
        self.txt = txt

e = A("e")
a = B("a")
k = C("k")
l = D("l")
i = E("i")
d = F("d")
b = B("b")
g = A("g")
c = D("c")
n = A("n")

e.t = a
e.w = b
a.r = i
k.t = b
k.s = c
k.o = e
k.u = a
k.p = i
l.u = k
l.x = k
i.z = a
d.o = c
d.s = e
d.w = n
b.r = i
g.t = b
g.w = b
c.u = k
c.x = k
n.t = b
n.w = b
assert i.z.r.z.r.z.r.z.txt == "
class A:
    def __init__(self, txt: str):
        self.t: B = None
        self.w: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: D = None
        self.o: A = None
        self.u: B = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: C = None
        self.x: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: D = None
        self.s: A = None
        self.w: A = None
        self.txt = txt

e = A("e")
a = B("a")
k = C("k")
l = D("l")
i = E("i")
d = F("d")
b = B("b")
g = A("g")
c = D("c")
n = A("n")

e.t = a
e.w = b
a.r = i
k.t = b
k.s = c
k.o = e
k.u = a
k.p = i
l.u = k
l.x = k
i.z = a
d.o = c
d.s = e
d.w = n
b.r = i
g.t = b
g.w = b
c.u = k
c.x = k
n.t = b
n.w = b
assert i.z.r.z.r.z.r.z.txt == "a"