class A:
    def __init__(self, txt: str):
        self.v: C = None
        self.w: I = None
        self.u: D = None
        self.p: G = None
        self.t: I = None
        self.q: C = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.p: G = None
        self.u: D = None
        self.w: D = None
        self.t: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.v: I = None
        self.w: B = None
        self.x: A = None
        self.y: G = None
        self.s: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: B = None
        self.w: B = None
        self.s: I = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.u: H = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.p: G = None
        self.u: D = None
        self.w: D = None
        self.t: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.v: I = None
        self.w: B = None
        self.x: A = None
        self.y: G = None
        self.s: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: B = None
        self.w: B = None
        self.s: I = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.u: H = None
        self.txt = txt

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

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

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

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