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

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

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

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.y: A = None
        self.t: F = None
        self.z: D = None
        self.v: G = None
        self.o: G = None
        self.q: A = None
        self.u: B = None
        self.p: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: G = None
        self.y: G = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.u: A = None
        self.s: G = None
        self.v: A = None
        self.y: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: G = None
        self.o: D = None
        self.x: A = None
        self.u: F = None
        self.z: F = None
        self.r: F = None
        self.p: D = None
        self.v: B = None
        self.txt = txt

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.y: A = None
        self.t: F = None
        self.z: D = None
        self.v: G = None
        self.o: G = None
        self.q: A = None
        self.u: B = None
        self.p: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: G = None
        self.y: G = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.u: A = None
        self.s: G = None
        self.v: A = None
        self.y: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: G = None
        self.o: D = None
        self.x: A = None
        self.u: F = None
        self.z: F = None
        self.r: F = None
        self.p: D = None
        self.v: B = None
        self.txt = txt

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

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

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