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

class B:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: D = None
        self.u: C = None
        self.z: A = None
        self.txt = txt

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: D = None
        self.u: C = None
        self.z: A = None
        self.txt = txt

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

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

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

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

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