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

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

class C:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: C = None
        self.w: C = None
        self.s: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.x: D = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: C = None
        self.v: A = None
        self.u: C = None
        self.s: A = None
        self.txt = txt

e = A("e")
c = B("c")
i = C("i")
k = D("k")
j = E("j")
b = E("b")
f = B("f")
g = C("g")
n = D("n")
m = C("m")

e.x = c
e.v = c
e.u = c
e.z = b
e.w = k
c.v = k
c.o = e
i.t = k
i.p = m
i.w = m
i.s = n
k.o = i
k.x = n
j.r = m
j.u = m
j.v = e
j.s = e
b.r = i
b.v = e
b.s = e
b.u = m
f.v = n
f.o = e
g.t = k
g.p = i
g.w = m
g.s = n
n.o = m
n.x = k
m.t = k
m.s = k
m.p = g
m.w = g
assert c.o.x.v.txt == "
class A:
    def __init__(self, txt: str):
        self.x: B = None
        self.z: E = None
        self.v: B = None
        self.w: D = None
        self.u: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: C = None
        self.w: C = None
        self.s: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.x: D = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: C = None
        self.v: A = None
        self.u: C = None
        self.s: A = None
        self.txt = txt

e = A("e")
c = B("c")
i = C("i")
k = D("k")
j = E("j")
b = E("b")
f = B("f")
g = C("g")
n = D("n")
m = C("m")

e.x = c
e.v = c
e.u = c
e.z = b
e.w = k
c.v = k
c.o = e
i.t = k
i.p = m
i.w = m
i.s = n
k.o = i
k.x = n
j.r = m
j.u = m
j.v = e
j.s = e
b.r = i
b.v = e
b.s = e
b.u = m
f.v = n
f.o = e
g.t = k
g.p = i
g.w = m
g.s = n
n.o = m
n.x = k
m.t = k
m.s = k
m.p = g
m.w = g
assert c.o.x.v.txt == "k"