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

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: B = None
        self.s: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: E = None
        self.q: D = None
        self.y: F = None
        self.r: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.u: D = None
        self.o: B = None
        self.z: A = None
        self.x: D = None
        self.txt = txt

i = A("i")
e = B("e")
f = C("f")
j = D("j")
c = E("c")
b = F("b")
k = B("k")

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

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: B = None
        self.s: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: E = None
        self.q: D = None
        self.y: F = None
        self.r: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.u: D = None
        self.o: B = None
        self.z: A = None
        self.x: D = None
        self.txt = txt

i = A("i")
e = B("e")
f = C("f")
j = D("j")
c = E("c")
b = F("b")
k = B("k")

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