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

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: G = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: A = None
        self.r: H = None
        self.o: J = None
        self.q: G = None
        self.s: E = None
        self.x: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: I = None
        self.o: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: G = None
        self.v: E = None
        self.s: I = None
        self.u: J = None
        self.o: D = None
        self.w: E = None
        self.q: D = None
        self.z: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: F = None
        self.r: A = None
        self.t: D = None
        self.txt = txt

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: G = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: A = None
        self.r: H = None
        self.o: J = None
        self.q: G = None
        self.s: E = None
        self.x: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: I = None
        self.o: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: G = None
        self.v: E = None
        self.s: I = None
        self.u: J = None
        self.o: D = None
        self.w: E = None
        self.q: D = None
        self.z: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: F = None
        self.r: A = None
        self.t: D = None
        self.txt = txt

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

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

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