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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: G = None
        self.s: C = None
        self.q: H = None
        self.z: I = None
        self.y: G = None
        self.r: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.u: B = None
        self.z: F = None
        self.s: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.z: C = None
        self.p: F = None
        self.r: G = None
        self.x: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.q: C = None
        self.w: J = None
        self.z: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: A = None
        self.s: B = None
        self.txt = txt

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: G = None
        self.s: C = None
        self.q: H = None
        self.z: I = None
        self.y: G = None
        self.r: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.u: B = None
        self.z: F = None
        self.s: J = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.z: C = None
        self.p: F = None
        self.r: G = None
        self.x: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.q: C = None
        self.w: J = None
        self.z: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: A = None
        self.s: B = None
        self.txt = txt

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

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