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

class B:
    def __init__(self, txt: str):
        self.p: C = None
        self.w: D = None
        self.y: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.s: A = None
        self.q: G = None
        self.v: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: G = None
        self.y: J = None
        self.t: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: I = None
        self.z: D = None
        self.p: A = None
        self.w: J = None
        self.t: E = None
        self.q: I = None
        self.x: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: B = None
        self.w: C = None
        self.o: I = None
        self.r: J = None
        self.y: D = None
        self.p: H = None
        self.q: A = None
        self.s: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: C = None
        self.z: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: D = None
        self.r: B = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: G = None
        self.u: I = None
        self.r: I = None
        self.o: D = None
        self.x: B = None
        self.s: H = None
        self.t: I = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.p: C = None
        self.w: D = None
        self.y: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.s: A = None
        self.q: G = None
        self.v: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: G = None
        self.y: J = None
        self.t: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: I = None
        self.z: D = None
        self.p: A = None
        self.w: J = None
        self.t: E = None
        self.q: I = None
        self.x: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: B = None
        self.w: C = None
        self.o: I = None
        self.r: J = None
        self.y: D = None
        self.p: H = None
        self.q: A = None
        self.s: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: C = None
        self.z: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: D = None
        self.r: B = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: G = None
        self.u: I = None
        self.r: I = None
        self.o: D = None
        self.x: B = None
        self.s: H = None
        self.t: I = None
        self.txt = txt

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

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