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

class B:
    def __init__(self, txt: str):
        self.o: F = None
        self.w: E = None
        self.txt = txt

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

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

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

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

k = A("k")
c = B("c")
m = C("m")
l = D("l")
e = E("e")
a = F("a")
n = C("n")
d = C("d")
f = C("f")
j = A("j")

k.o = n
k.v = j
c.o = a
c.w = e
m.y = c
m.u = c
m.z = l
m.w = e
m.v = e
l.v = e
l.q = e
l.x = a
l.w = a
e.x = l
e.v = f
e.s = j
e.z = a
e.o = m
e.y = m
a.s = c
a.w = c
a.z = e
n.y = c
n.u = c
n.z = l
n.w = e
n.v = e
d.y = c
d.u = c
d.z = l
d.w = e
d.v = e
f.y = c
f.u = c
f.z = l
f.w = e
f.v = e
j.o = f
j.v = k
assert d.u.o.w.o.z.s.v.txt == "
class A:
    def __init__(self, txt: str):
        self.o: C = None
        self.v: A = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: F = None
        self.w: E = None
        self.txt = txt

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

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

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

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

k = A("k")
c = B("c")
m = C("m")
l = D("l")
e = E("e")
a = F("a")
n = C("n")
d = C("d")
f = C("f")
j = A("j")

k.o = n
k.v = j
c.o = a
c.w = e
m.y = c
m.u = c
m.z = l
m.w = e
m.v = e
l.v = e
l.q = e
l.x = a
l.w = a
e.x = l
e.v = f
e.s = j
e.z = a
e.o = m
e.y = m
a.s = c
a.w = c
a.z = e
n.y = c
n.u = c
n.z = l
n.w = e
n.v = e
d.y = c
d.u = c
d.z = l
d.w = e
d.v = e
f.y = c
f.u = c
f.z = l
f.w = e
f.v = e
j.o = f
j.v = k
assert d.u.o.w.o.z.s.v.txt == "k"