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

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

class C:
    def __init__(self, txt: str):
        self.p: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: E = None
        self.p: I = None
        self.s: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.w: B = None
        self.t: B = None
        self.u: I = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: E = None
        self.p: I = None
        self.s: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.w: B = None
        self.t: B = None
        self.u: I = None
        self.txt = txt

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

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

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