class A:
    def __init__(self, txt: str):
        self.y: E = None
        self.u: B = None
        self.v: C = None
        self.q: B = None
        self.w: J = None
        self.r: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.r: J = None
        self.txt = txt

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

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

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

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

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.r: J = None
        self.txt = txt

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

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

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

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

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

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

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

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

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

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