class A:
    def __init__(self, txt: str):
        self.w: F = None
        self.p: J = None
        self.y: H = None
        self.u: D = None
        self.o: E = None
        self.z: F = None
        self.r: B = None
        self.t: H = None
        self.v: B = None
        self.q: F = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.s: G = None
        self.q: H = None
        self.p: J = None
        self.r: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.z: D = None
        self.u: H = None
        self.w: C = None
        self.t: C = None
        self.o: B = None
        self.s: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: F = None
        self.x: C = None
        self.w: G = None
        self.s: D = None
        self.txt = txt

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

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

i = A("i")
b = B("b")
l = C("l")
c = D("c")
d = E("d")
e = F("e")
h = G("h")
j = H("j")
f = I("f")
a = J("a")

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

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

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

class D:
    def __init__(self, txt: str):
        self.s: G = None
        self.q: H = None
        self.p: J = None
        self.r: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.z: D = None
        self.u: H = None
        self.w: C = None
        self.t: C = None
        self.o: B = None
        self.s: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: F = None
        self.x: C = None
        self.w: G = None
        self.s: D = None
        self.txt = txt

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

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

i = A("i")
b = B("b")
l = C("l")
c = D("c")
d = E("d")
e = F("e")
h = G("h")
j = H("j")
f = I("f")
a = J("a")

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