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

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: G = None
        self.u: C = None
        self.x: A = None
        self.w: H = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: F = None
        self.z: G = None
        self.p: B = None
        self.x: B = None
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: F = None
        self.s: I = None
        self.x: D = None
        self.o: C = None
        self.p: C = None
        self.y: A = None
        self.w: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.r: D = None
        self.y: E = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: G = None
        self.u: C = None
        self.x: A = None
        self.w: H = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: F = None
        self.z: G = None
        self.p: B = None
        self.x: B = None
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: F = None
        self.s: I = None
        self.x: D = None
        self.o: C = None
        self.p: C = None
        self.y: A = None
        self.w: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.r: D = None
        self.y: E = None
        self.txt = txt

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

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