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

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

class C:
    def __init__(self, txt: str):
        self.z: F = None
        self.w: B = None
        self.y: E = None
        self.t: B = None
        self.x: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.q: F = None
        self.x: D = None
        self.u: F = None
        self.p: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.o: E = None
        self.r: C = None
        self.q: C = None
        self.txt = txt

c = A("c")
i = B("i")
e = C("e")
j = D("j")
l = E("l")
m = F("m")
b = B("b")

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

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

class C:
    def __init__(self, txt: str):
        self.z: F = None
        self.w: B = None
        self.y: E = None
        self.t: B = None
        self.x: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.q: F = None
        self.x: D = None
        self.u: F = None
        self.p: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.o: E = None
        self.r: C = None
        self.q: C = None
        self.txt = txt

c = A("c")
i = B("i")
e = C("e")
j = D("j")
l = E("l")
m = F("m")
b = B("b")

c.x = l
c.u = b
c.v = j
c.s = i
i.v = m
i.t = m
i.s = b
i.w = l
i.q = l
e.z = m
e.w = i
e.t = i
e.y = l
e.x = l
j.r = b
j.u = c
j.q = c
j.p = l
j.w = e
l.s = e
l.p = e
l.q = m
l.u = m
l.x = j
m.t = j
m.o = l
m.r = e
m.q = e
b.v = m
b.t = m
b.s = i
b.w = l
b.q = l
assert m.o.x.p.u.t.u.v.txt == "j"