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

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

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

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

class E:
    def __init__(self, txt: str):
        self.u: I = None
        self.w: B = None
        self.z: C = None
        self.t: D = None
        self.o: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.o: C = None
        self.z: I = None
        self.u: A = None
        self.y: D = None
        self.s: B = None
        self.q: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.w: E = None
        self.v: H = None
        self.r: B = None
        self.o: C = None
        self.u: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: G = None
        self.t: I = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: B = None
        self.v: C = None
        self.p: F = None
        self.s: B = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.u: I = None
        self.w: B = None
        self.z: C = None
        self.t: D = None
        self.o: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.o: C = None
        self.z: I = None
        self.u: A = None
        self.y: D = None
        self.s: B = None
        self.q: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.w: E = None
        self.v: H = None
        self.r: B = None
        self.o: C = None
        self.u: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: G = None
        self.t: I = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: B = None
        self.v: C = None
        self.p: F = None
        self.s: B = None
        self.txt = txt

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

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