class A:
    def __init__(self, txt: str):
        self.u: I = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.t: E = None
        self.o: A = None
        self.r: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: H = None
        self.p: I = None
        self.u: B = None
        self.t: J = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: J = None
        self.r: I = None
        self.t: A = None
        self.q: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: J = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.p: F = None
        self.y: C = None
        self.s: C = None
        self.r: J = None
        self.u: D = None
        self.z: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: D = None
        self.t: F = None
        self.o: H = None
        self.p: G = None
        self.q: D = None
        self.r: C = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.u: E = None
        self.txt = txt

l = A("l")
g = B("g")
m = C("m")
k = D("k")
n = E("n")
a = F("a")
j = G("j")
h = H("h")
e = I("e")
f = J("f")

l.u = e
g.z = h
g.t = n
g.o = l
g.r = j
m.y = h
m.p = e
m.u = g
m.t = f
k.w = f
k.r = e
k.t = l
k.q = l
n.t = f
a.v = g
a.y = g
a.p = l
a.o = e
a.s = h
a.r = h
a.q = k
a.z = j
j.u = g
j.z = h
j.t = h
j.r = h
j.x = k
j.y = k
j.q = l
j.s = m
h.w = a
h.p = a
h.y = m
h.s = m
h.r = f
h.u = k
h.z = j
e.z = k
e.q = k
e.t = a
e.o = h
e.p = j
e.r = m
f.u = n
assert m.t.u.t.u.t.u.txt == "
class A:
    def __init__(self, txt: str):
        self.u: I = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.t: E = None
        self.o: A = None
        self.r: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: H = None
        self.p: I = None
        self.u: B = None
        self.t: J = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: J = None
        self.r: I = None
        self.t: A = None
        self.q: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: J = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.p: F = None
        self.y: C = None
        self.s: C = None
        self.r: J = None
        self.u: D = None
        self.z: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: D = None
        self.t: F = None
        self.o: H = None
        self.p: G = None
        self.q: D = None
        self.r: C = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.u: E = None
        self.txt = txt

l = A("l")
g = B("g")
m = C("m")
k = D("k")
n = E("n")
a = F("a")
j = G("j")
h = H("h")
e = I("e")
f = J("f")

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