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

class B:
    def __init__(self, txt: str):
        self.z: I = None
        self.u: C = None
        self.o: C = None
        self.q: D = None
        self.s: C = None
        self.t: I = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: E = None
        self.txt = txt

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.v: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: J = None
        self.w: J = None
        self.v: H = None
        self.txt = txt

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

c = A("c")
b = B("b")
l = C("l")
n = D("n")
e = E("e")
g = F("g")
d = G("d")
j = H("j")
k = I("k")
a = J("a")

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

class B:
    def __init__(self, txt: str):
        self.z: I = None
        self.u: C = None
        self.o: C = None
        self.q: D = None
        self.s: C = None
        self.t: I = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: E = None
        self.txt = txt

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.v: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: J = None
        self.w: J = None
        self.v: H = None
        self.txt = txt

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

c = A("c")
b = B("b")
l = C("l")
n = D("n")
e = E("e")
g = F("g")
d = G("d")
j = H("j")
k = I("k")
a = J("a")

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