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

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.v: F = None
        self.y: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: J = None
        self.v: J = 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.u: J = None
        self.y: C = None
        self.z: F = None
        self.q: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.v: J = None
        self.o: H = None
        self.y: F = None
        self.u: H = None
        self.z: E = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: A = None
        self.y: D = None
        self.txt = txt

l = A("l")
e = B("e")
b = C("b")
j = D("j")
h = E("h")
c = F("c")
i = G("i")
a = H("a")
n = I("n")
d = J("d")

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

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.v: F = None
        self.y: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: J = None
        self.v: J = 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.u: J = None
        self.y: C = None
        self.z: F = None
        self.q: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.v: J = None
        self.o: H = None
        self.y: F = None
        self.u: H = None
        self.z: E = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: A = None
        self.y: D = None
        self.txt = txt

l = A("l")
e = B("e")
b = C("b")
j = D("j")
h = E("h")
c = F("c")
i = G("i")
a = H("a")
n = I("n")
d = J("d")

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