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

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

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: A = None
        self.z: B = None
        self.x: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: D = None
        self.q: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: J = None
        self.y: B = None
        self.w: C = None
        self.o: G = None
        self.q: B = None
        self.x: A = None
        self.p: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: J = None
        self.s: G = None
        self.z: B = None
        self.u: C = None
        self.v: D = None
        self.o: F = None
        self.t: D = None
        self.w: H = None
        self.x: J = None
        self.q: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: C = None
        self.v: C = None
        self.s: A = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: A = None
        self.z: B = None
        self.x: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: D = None
        self.q: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: J = None
        self.y: B = None
        self.w: C = None
        self.o: G = None
        self.q: B = None
        self.x: A = None
        self.p: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: J = None
        self.s: G = None
        self.z: B = None
        self.u: C = None
        self.v: D = None
        self.o: F = None
        self.t: D = None
        self.w: H = None
        self.x: J = None
        self.q: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: C = None
        self.v: C = None
        self.s: A = None
        self.txt = txt

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

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