class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.w: J = None
        self.s: B = None
        self.t: F = None
        self.v: F = None
        self.r: B = None
        self.o: J = None
        self.p: I = None
        self.y: C = None
        self.x: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: J = None
        self.t: A = None
        self.r: F = None
        self.v: D = None
        self.u: G = None
        self.y: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: E = None
        self.v: E = None
        self.q: F = None
        self.w: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: A = None
        self.v: J = None
        self.p: B = None
        self.t: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.x: C = None
        self.v: C = None
        self.o: A = None
        self.t: D = None
        self.y: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.w: J = None
        self.t: A = None
        self.r: F = None
        self.v: D = None
        self.u: G = None
        self.y: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: E = None
        self.v: E = None
        self.q: F = None
        self.w: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: A = None
        self.v: J = None
        self.p: B = None
        self.t: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.x: C = None
        self.v: C = None
        self.o: A = None
        self.t: D = None
        self.y: B = None
        self.txt = txt

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

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