class A:
    def __init__(self, txt: str):
        self.y: I = None
        self.t: H = None
        self.q: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: I = None
        self.y: I = None
        self.u: G = None
        self.t: C = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: E = None
        self.v: C = None
        self.txt = txt

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

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

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

b = A("b")
d = B("d")
e = C("e")
c = D("c")
m = E("m")
f = F("f")
n = G("n")
g = H("g")
k = I("k")

b.y = k
b.t = g
b.q = m
d.x = k
d.y = k
d.u = n
d.t = e
e.x = k
c.s = e
c.x = e
c.u = e
c.v = n
c.y = d
c.r = d
c.o = g
c.z = m
c.w = b
m.q = f
m.x = g
m.p = g
m.z = e
m.t = d
m.r = c
f.w = m
f.v = e
n.o = m
n.t = m
n.s = d
g.t = e
g.r = e
g.u = d
g.w = d
g.x = b
g.s = b
g.y = n
g.q = f
g.v = k
k.r = g
k.u = n
k.w = b
k.o = c
k.z = d
assert k.u.s.x.o.v.t.t.t.x.txt == "
class A:
    def __init__(self, txt: str):
        self.y: I = None
        self.t: H = None
        self.q: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: I = None
        self.y: I = None
        self.u: G = None
        self.t: C = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.w: E = None
        self.v: C = None
        self.txt = txt

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

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

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

b = A("b")
d = B("d")
e = C("e")
c = D("c")
m = E("m")
f = F("f")
n = G("n")
g = H("g")
k = I("k")

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