class A:
    def __init__(self, txt: str):
        self.w: B = None
        self.u: C = None
        self.x: E = None
        self.y: E = None
        self.txt = txt

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.s: F = None
        self.txt = txt

b = A("b")
c = B("c")
n = C("n")
d = D("d")
e = E("e")
f = F("f")
a = B("a")
i = C("i")
g = F("g")
j = D("j")

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.s: F = None
        self.txt = txt

b = A("b")
c = B("c")
n = C("n")
d = D("d")
e = E("e")
f = F("f")
a = B("a")
i = C("i")
g = F("g")
j = D("j")

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