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

class B:
    def __init__(self, txt: str):
        self.x: I = None
        self.t: C = None
        self.y: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.o: F = None
        self.x: I = None
        self.t: F = None
        self.r: B = None
        self.z: F = None
        self.q: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: A = None
        self.r: A = None
        self.w: G = None
        self.z: I = None
        self.x: H = None
        self.t: H = None
        self.u: C = None
        self.p: B = None
        self.q: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.x: J = None
        self.o: H = None
        self.w: F = None
        self.v: E = None
        self.z: I = None
        self.r: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: I = None
        self.t: B = None
        self.w: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: E = None
        self.x: G = None
        self.r: H = None
        self.u: F = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: E = None
        self.q: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.x: I = None
        self.t: C = None
        self.y: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: F = None
        self.o: F = None
        self.x: I = None
        self.t: F = None
        self.r: B = None
        self.z: F = None
        self.q: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: A = None
        self.r: A = None
        self.w: G = None
        self.z: I = None
        self.x: H = None
        self.t: H = None
        self.u: C = None
        self.p: B = None
        self.q: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.x: J = None
        self.o: H = None
        self.w: F = None
        self.v: E = None
        self.z: I = None
        self.r: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: I = None
        self.t: B = None
        self.w: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: E = None
        self.x: G = None
        self.r: H = None
        self.u: F = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: E = None
        self.q: D = None
        self.txt = txt

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

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