class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.z: H = None
        self.r: I = None
        self.q: C = None
        self.x: F = None
        self.w: I = None
        self.v: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: F = None
        self.t: C = None
        self.x: D = None
        self.r: G = None
        self.z: A = None
        self.v: D = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: I = None
        self.r: D = None
        self.y: J = None
        self.q: J = None
        self.x: B = None
        self.o: J = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: G = None
        self.z: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.u: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: B = None
        self.u: B = None
        self.q: E = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: D = None
        self.o: C = None
        self.t: C = None
        self.u: D = None
        self.r: C = None
        self.z: F = None
        self.w: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.w: F = None
        self.t: C = None
        self.x: D = None
        self.r: G = None
        self.z: A = None
        self.v: D = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: I = None
        self.r: D = None
        self.y: J = None
        self.q: J = None
        self.x: B = None
        self.o: J = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: G = None
        self.z: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.u: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: B = None
        self.u: B = None
        self.q: E = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: D = None
        self.o: C = None
        self.t: C = None
        self.u: D = None
        self.r: C = None
        self.z: F = None
        self.w: D = None
        self.txt = txt

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

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