class A:
    def __init__(self, txt: str):
        self.q: E = None
        self.x: A = None
        self.p: E = None
        self.y: E = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: F = None
        self.v: D = None
        self.y: C = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.p: C = None
        self.o: A = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.w: F = None
        self.v: D = None
        self.y: C = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.p: C = None
        self.o: A = None
        self.txt = txt

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

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