class A:
    def __init__(self, txt: str):
        self.x: C = None
        self.u: C = None
        self.w: I = None
        self.y: J = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: E = None
        self.r: J = None
        self.t: I = None
        self.y: A = None
        self.s: G = None
        self.p: J = None
        self.o: I = None
        self.v: D = None
        self.w: G = None
        self.u: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.q: F = None
        self.v: E = None
        self.w: J = None
        self.x: A = None
        self.o: B = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: C = None
        self.z: E = None
        self.s: C = None
        self.t: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: G = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: I = None
        self.o: F = None
        self.t: H = None
        self.x: A = None
        self.s: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.q: E = None
        self.r: J = None
        self.t: I = None
        self.y: A = None
        self.s: G = None
        self.p: J = None
        self.o: I = None
        self.v: D = None
        self.w: G = None
        self.u: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.q: F = None
        self.v: E = None
        self.w: J = None
        self.x: A = None
        self.o: B = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: C = None
        self.z: E = None
        self.s: C = None
        self.t: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: G = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: I = None
        self.o: F = None
        self.t: H = None
        self.x: A = None
        self.s: A = None
        self.txt = txt

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

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