class A:
    def __init__(self, txt: str):
        self.w: E = None
        self.y: F = None
        self.v: B = None
        self.z: G = None
        self.q: E = None
        self.r: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.p: G = None
        self.t: D = None
        self.q: D = None
        self.v: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: H = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.t: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: G = None
        self.p: B = None
        self.t: B = None
        self.u: A = None
        self.r: B = None
        self.q: A = None
        self.w: B = None
        self.o: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.p: G = None
        self.t: D = None
        self.q: D = None
        self.v: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: H = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.t: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: G = None
        self.p: B = None
        self.t: B = None
        self.u: A = None
        self.r: B = None
        self.q: A = None
        self.w: B = None
        self.o: D = None
        self.txt = txt

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

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