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

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.q: B = None
        self.o: F = None
        self.v: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: C = None
        self.s: C = None
        self.o: C = None
        self.v: B = None
        self.z: A = None
        self.txt = txt

k = A("k")
j = B("j")
h = C("h")
n = D("n")
i = E("i")
a = F("a")
c = F("c")
l = D("l")
e = A("e")

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.q: B = None
        self.o: F = None
        self.v: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: C = None
        self.s: C = None
        self.o: C = None
        self.v: B = None
        self.z: A = None
        self.txt = txt

k = A("k")
j = B("j")
h = C("h")
n = D("n")
i = E("i")
a = F("a")
c = F("c")
l = D("l")
e = A("e")

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