class A:
    def __init__(self, txt: str):
        self.z: F = None
        self.o: B = None
        self.y: D = None
        self.s: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.o: I = None
        self.r: E = None
        self.w: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: E = None
        self.x: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: G = None
        self.o: C = None
        self.x: A = None
        self.r: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: G = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.o: I = None
        self.r: E = None
        self.w: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: E = None
        self.x: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: G = None
        self.o: C = None
        self.x: A = None
        self.r: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: G = None
        self.txt = txt

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

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