class A:
    def __init__(self, txt: str):
        self.x: C = None
        self.t: C = None
        self.u: F = None
        self.v: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: A = None
        self.q: F = None
        self.t: A = None
        self.y: E = None
        self.s: A = None
        self.w: E = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.z: G = None
        self.w: F = None
        self.t: A = None
        self.y: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: D = None
        self.w: E = None
        self.u: D = None
        self.s: A = None
        self.q: B = None
        self.o: A = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: A = None
        self.q: F = None
        self.t: A = None
        self.y: E = None
        self.s: A = None
        self.w: E = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.z: G = None
        self.w: F = None
        self.t: A = None
        self.y: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: D = None
        self.w: E = None
        self.u: D = None
        self.s: A = None
        self.q: B = None
        self.o: A = None
        self.txt = txt

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

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

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

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