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

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

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.o: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.o: B = None
        self.t: G = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: B = None
        self.v: I = None
        self.q: E = None
        self.s: C = None
        self.t: I = None
        self.x: J = None
        self.z: E = None
        self.r: D = None
        self.o: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: D = None
        self.r: A = None
        self.w: A = None
        self.z: F = None
        self.t: A = None
        self.p: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: H = None
        self.x: F = None
        self.v: D = None
        self.t: A = None
        self.txt = txt

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.o: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.o: B = None
        self.t: G = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: B = None
        self.v: I = None
        self.q: E = None
        self.s: C = None
        self.t: I = None
        self.x: J = None
        self.z: E = None
        self.r: D = None
        self.o: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: D = None
        self.r: A = None
        self.w: A = None
        self.z: F = None
        self.t: A = None
        self.p: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: H = None
        self.x: F = None
        self.v: D = None
        self.t: A = None
        self.txt = txt

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

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

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