class A:
    def __init__(self, txt: str):
        self.z: D = None
        self.t: E = None
        self.y: B = None
        self.r: B = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.s: A = None
        self.w: A = None
        self.z: A = None
        self.t: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: F = None
        self.p: B = None
        self.r: D = None
        self.y: A = None
        self.v: F = None
        self.txt = txt

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

k = A("k")
b = B("b")
i = C("i")
j = D("j")
g = E("g")
a = F("a")
d = C("d")
l = C("l")
c = E("c")

k.z = j
k.t = g
k.y = b
k.r = b
b.v = c
b.z = l
i.t = a
i.s = a
i.w = a
i.p = j
i.o = c
i.z = b
j.s = k
j.w = k
j.z = k
j.t = c
g.u = a
g.v = a
g.p = b
g.r = j
g.y = k
a.u = i
a.y = j
a.w = k
a.q = k
a.t = b
a.r = l
d.t = a
d.s = a
d.w = a
d.p = j
d.o = g
d.z = b
l.t = a
l.s = a
l.w = a
l.p = j
l.o = g
l.z = b
c.u = a
c.v = a
c.p = b
c.r = j
c.y = k
assert d.o.p.v.u.u.p.w.txt == "
class A:
    def __init__(self, txt: str):
        self.z: D = None
        self.t: E = None
        self.y: B = None
        self.r: B = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.s: A = None
        self.w: A = None
        self.z: A = None
        self.t: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: F = None
        self.p: B = None
        self.r: D = None
        self.y: A = None
        self.v: F = None
        self.txt = txt

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

k = A("k")
b = B("b")
i = C("i")
j = D("j")
g = E("g")
a = F("a")
d = C("d")
l = C("l")
c = E("c")

k.z = j
k.t = g
k.y = b
k.r = b
b.v = c
b.z = l
i.t = a
i.s = a
i.w = a
i.p = j
i.o = c
i.z = b
j.s = k
j.w = k
j.z = k
j.t = c
g.u = a
g.v = a
g.p = b
g.r = j
g.y = k
a.u = i
a.y = j
a.w = k
a.q = k
a.t = b
a.r = l
d.t = a
d.s = a
d.w = a
d.p = j
d.o = g
d.z = b
l.t = a
l.s = a
l.w = a
l.p = j
l.o = g
l.z = b
c.u = a
c.v = a
c.p = b
c.r = j
c.y = k
assert d.o.p.v.u.u.p.w.txt == "k"