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

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

class C:
    def __init__(self, txt: str):
        self.p: A = None
        self.s: A = None
        self.q: I = None
        self.u: E = None
        self.z: H = None
        self.r: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.y: I = None
        self.v: G = None
        self.t: G = None
        self.s: F = None
        self.z: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: B = None
        self.o: F = None
        self.u: A = None
        self.t: A = None
        self.z: D = None
        self.v: G = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: F = None
        self.t: E = None
        self.u: I = None
        self.p: F = None
        self.v: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: A = None
        self.v: D = None
        self.o: I = None
        self.s: D = None
        self.w: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: D = None
        self.v: G = None
        self.y: C = None
        self.s: B = None
        self.w: B = None
        self.z: G = None
        self.o: D = None
        self.r: F = None
        self.t: G = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: A = None
        self.s: A = None
        self.q: I = None
        self.u: E = None
        self.z: H = None
        self.r: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.y: I = None
        self.v: G = None
        self.t: G = None
        self.s: F = None
        self.z: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: B = None
        self.o: F = None
        self.u: A = None
        self.t: A = None
        self.z: D = None
        self.v: G = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: F = None
        self.t: E = None
        self.u: I = None
        self.p: F = None
        self.v: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: A = None
        self.v: D = None
        self.o: I = None
        self.s: D = None
        self.w: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: D = None
        self.v: G = None
        self.y: C = None
        self.s: B = None
        self.w: B = None
        self.z: G = None
        self.o: D = None
        self.r: F = None
        self.t: G = None
        self.txt = txt

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

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