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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.t: C = None
        self.x: C = None
        self.s: E = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.y: B = None
        self.u: D = None
        self.o: E = None
        self.w: D = None
        self.t: F = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.t: C = None
        self.x: C = None
        self.s: E = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.y: B = None
        self.u: D = None
        self.o: E = None
        self.w: D = None
        self.t: F = None
        self.txt = txt

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

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