class A:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: F = None
        self.y: C = None
        self.o: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: A = None
        self.v: B = None
        self.p: B = None
        self.t: D = None
        self.y: F = None
        self.w: B = None
        self.txt = txt

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

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

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

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

i.t = f
i.o = f
i.p = k
i.y = b
h.s = g
j.q = i
j.v = g
j.p = h
j.w = h
j.t = f
j.y = k
f.o = d
f.t = b
f.w = h
e.o = g
e.w = j
e.p = f
e.r = f
e.y = k
k.p = e
d.q = i
d.v = h
d.p = h
d.w = h
d.t = f
d.y = k
g.s = h
a.o = h
a.w = b
a.p = f
a.r = f
a.y = k
b.q = i
b.v = h
b.p = g
b.w = g
b.t = f
b.y = k
assert j.q.p.p.w.q.y.t.t.txt == "
class A:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: F = None
        self.y: C = None
        self.o: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: A = None
        self.v: B = None
        self.p: B = None
        self.t: D = None
        self.y: F = None
        self.w: B = None
        self.txt = txt

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

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

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

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

i.t = f
i.o = f
i.p = k
i.y = b
h.s = g
j.q = i
j.v = g
j.p = h
j.w = h
j.t = f
j.y = k
f.o = d
f.t = b
f.w = h
e.o = g
e.w = j
e.p = f
e.r = f
e.y = k
k.p = e
d.q = i
d.v = h
d.p = h
d.w = h
d.t = f
d.y = k
g.s = h
a.o = h
a.w = b
a.p = f
a.r = f
a.y = k
b.q = i
b.v = h
b.p = g
b.w = g
b.t = f
b.y = k
assert j.q.p.p.w.q.y.t.t.txt == "b"