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

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

class C:
    def __init__(self, txt: str):
        self.y: F = None
        self.x: D = None
        self.r: D = None
        self.q: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: I = None
        self.o: B = None
        self.q: F = None
        self.s: I = None
        self.v: I = None
        self.r: A = None
        self.w: F = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.o: C = None
        self.u: C = None
        self.s: E = None
        self.y: G = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: I = None
        self.p: D = None
        self.u: D = None
        self.x: H = None
        self.q: I = None
        self.r: E = None
        self.y: F = None
        self.o: F = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.y: F = None
        self.x: D = None
        self.r: D = None
        self.q: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: I = None
        self.o: B = None
        self.q: F = None
        self.s: I = None
        self.v: I = None
        self.r: A = None
        self.w: F = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.o: C = None
        self.u: C = None
        self.s: E = None
        self.y: G = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: I = None
        self.p: D = None
        self.u: D = None
        self.x: H = None
        self.q: I = None
        self.r: E = None
        self.y: F = None
        self.o: F = None
        self.txt = txt

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

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