class A:
    def __init__(self, txt: str):
        self.r: B = None
        self.t: J = None
        self.y: C = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.p: I = None
        self.r: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: J = None
        self.x: C = None
        self.v: B = None
        self.z: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.y: I = None
        self.z: I = None
        self.x: J = None
        self.t: D = None
        self.u: G = None
        self.p: J = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: E = None
        self.r: A = None
        self.p: J = None
        self.u: E = None
        self.v: F = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: E = None
        self.y: J = None
        self.r: C = None
        self.q: F = None
        self.x: J = None
        self.txt = txt

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.p: I = None
        self.r: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: J = None
        self.x: C = None
        self.v: B = None
        self.z: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.y: I = None
        self.z: I = None
        self.x: J = None
        self.t: D = None
        self.u: G = None
        self.p: J = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: E = None
        self.r: A = None
        self.p: J = None
        self.u: E = None
        self.v: F = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: E = None
        self.y: J = None
        self.r: C = None
        self.q: F = None
        self.x: J = None
        self.txt = txt

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

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

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