class A:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.q: F = None
        self.o: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: A = None
        self.s: A = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.r: C = None
        self.w: F = None
        self.y: D = None
        self.o: B = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.y: D = None
        self.o: A = None
        self.z: D = None
        self.p: B = None
        self.w: F = None
        self.u: H = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.q: F = None
        self.o: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: A = None
        self.s: A = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.r: C = None
        self.w: F = None
        self.y: D = None
        self.o: B = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.y: D = None
        self.o: A = None
        self.z: D = None
        self.p: B = None
        self.w: F = None
        self.u: H = None
        self.txt = txt

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

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