class A:
    def __init__(self, txt: str):
        self.y: I = None
        self.o: I = None
        self.x: H = None
        self.q: C = None
        self.v: B = None
        self.s: C = None
        self.u: D = None
        self.p: D = None
        self.t: E = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: A = None
        self.o: I = None
        self.u: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: I = None
        self.w: G = None
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.w: A = None
        self.s: G = None
        self.u: I = None
        self.z: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: F = None
        self.o: I = None
        self.z: C = None
        self.s: I = None
        self.w: E = None
        self.r: A = None
        self.v: F = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.r: B = None
        self.z: I = None
        self.q: D = None
        self.v: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: B = None
        self.v: H = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: A = None
        self.o: I = None
        self.u: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: I = None
        self.w: G = None
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.w: A = None
        self.s: G = None
        self.u: I = None
        self.z: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: F = None
        self.o: I = None
        self.z: C = None
        self.s: I = None
        self.w: E = None
        self.r: A = None
        self.v: F = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.r: B = None
        self.z: I = None
        self.q: D = None
        self.v: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: B = None
        self.v: H = None
        self.txt = txt

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

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