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

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

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.w: B = None
        self.r: E = None
        self.v: E = None
        self.x: E = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.w: B = None
        self.r: E = None
        self.v: E = None
        self.x: E = None
        self.txt = txt

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

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

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

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

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