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

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

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

class D:
    def __init__(self, txt: str):
        self.q: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: C = None
        self.q: B = None
        self.txt = txt

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

i = A("i")
e = B("e")
l = C("l")
d = D("d")
n = E("n")
j = F("j")
b = C("b")

i.v = d
i.s = d
i.t = e
e.p = b
e.y = b
e.w = l
e.s = j
l.z = d
l.t = e
l.w = i
l.r = j
d.q = n
n.p = b
n.q = e
j.r = e
j.x = b
j.q = i
b.z = d
b.t = e
b.w = i
b.r = j
assert n.p.z.q.p.z.q.q.txt == "
class A:
    def __init__(self, txt: str):
        self.v: D = None
        self.s: D = None
        self.t: B = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.q: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: C = None
        self.q: B = None
        self.txt = txt

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

i = A("i")
e = B("e")
l = C("l")
d = D("d")
n = E("n")
j = F("j")
b = C("b")

i.v = d
i.s = d
i.t = e
e.p = b
e.y = b
e.w = l
e.s = j
l.z = d
l.t = e
l.w = i
l.r = j
d.q = n
n.p = b
n.q = e
j.r = e
j.x = b
j.q = i
b.z = d
b.t = e
b.w = i
b.r = j
assert n.p.z.q.p.z.q.q.txt == "e"