class A:
    def __init__(self, txt: str):
        self.y: G = None
        self.v: G = None
        self.u: H = None
        self.t: B = None
        self.p: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: A = None
        self.r: D = None
        self.o: D = None
        self.q: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.s: A = None
        self.u: G = None
        self.v: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.v: G = None
        self.s: F = None
        self.p: B = None
        self.y: D = None
        self.z: F = None
        self.o: D = None
        self.q: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.w: C = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: E = None
        self.t: F = None
        self.txt = txt

i = A("i")
b = B("b")
a = C("a")
l = D("l")
g = E("g")
k = F("k")
d = G("d")
c = H("c")

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

class B:
    def __init__(self, txt: str):
        self.y: A = None
        self.r: D = None
        self.o: D = None
        self.q: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.s: A = None
        self.u: G = None
        self.v: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.v: G = None
        self.s: F = None
        self.p: B = None
        self.y: D = None
        self.z: F = None
        self.o: D = None
        self.q: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.w: C = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: E = None
        self.t: F = None
        self.txt = txt

i = A("i")
b = B("b")
a = C("a")
l = D("l")
g = E("g")
k = F("k")
d = G("d")
c = H("c")

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