class A:
    def __init__(self, txt: str):
        self.s: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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

k = A("k")
i = B("i")
h = C("h")
g = D("g")
a = E("a")
j = A("j")
e = C("e")

k.s = i
k.y = i
i.t = a
h.t = g
h.s = g
h.o = i
h.q = a
g.u = i
g.r = j
g.s = a
g.y = a
a.u = i
a.v = j
j.s = i
j.y = i
e.t = g
e.s = g
e.o = i
e.q = a
assert a.v.s.t.u.t.u.txt == "
class A:
    def __init__(self, txt: str):
        self.s: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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

k = A("k")
i = B("i")
h = C("h")
g = D("g")
a = E("a")
j = A("j")
e = C("e")

k.s = i
k.y = i
i.t = a
h.t = g
h.s = g
h.o = i
h.q = a
g.u = i
g.r = j
g.s = a
g.y = a
a.u = i
a.v = j
j.s = i
j.y = i
e.t = g
e.s = g
e.o = i
e.q = a
assert a.v.s.t.u.t.u.txt == "i"