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

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

class C:
    def __init__(self, txt: str):
        self.v: H = None
        self.u: H = None
        self.t: A = None
        self.o: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: I = None
        self.w: B = None
        self.x: D = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.v: H = None
        self.u: H = None
        self.t: A = None
        self.o: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: I = None
        self.w: B = None
        self.x: D = None
        self.txt = txt

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

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

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

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

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