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

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

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

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

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

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

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

i.s = a
i.u = l
i.o = l
i.z = h
b.t = h
b.o = a
b.s = a
b.p = a
b.w = l
h.p = b
h.y = a
h.r = f
l.u = i
k.y = h
k.q = a
k.w = l
k.z = l
k.u = i
k.t = i
a.w = i
a.x = i
a.r = h
a.q = f
a.s = f
a.y = n
f.t = h
f.o = a
f.s = a
f.p = a
f.w = l
n.t = h
n.o = a
n.s = a
n.p = a
n.w = l
assert i.u.u.s.r.y.s.w.txt == "
class A:
    def __init__(self, txt: str):
        self.s: F = None
        self.u: D = None
        self.o: D = None
        self.z: C = None
        self.txt = txt

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

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

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

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

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

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

i.s = a
i.u = l
i.o = l
i.z = h
b.t = h
b.o = a
b.s = a
b.p = a
b.w = l
h.p = b
h.y = a
h.r = f
l.u = i
k.y = h
k.q = a
k.w = l
k.z = l
k.u = i
k.t = i
a.w = i
a.x = i
a.r = h
a.q = f
a.s = f
a.y = n
f.t = h
f.o = a
f.s = a
f.p = a
f.w = l
n.t = h
n.o = a
n.s = a
n.p = a
n.w = l
assert i.u.u.s.r.y.s.w.txt == "l"