class A:
    def __init__(self, txt: str):
        self.r: F = None
        self.x: J = None
        self.y: D = None
        self.q: F = None
        self.u: C = None
        self.o: J = None
        self.s: D = None
        self.p: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: D = None
        self.v: A = None
        self.t: G = None
        self.q: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: G = None
        self.r: J = None
        self.t: E = None
        self.v: A = None
        self.o: G = None
        self.u: B = None
        self.y: J = None
        self.z: D = None
        self.w: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: A = None
        self.s: I = None
        self.z: J = None
        self.r: I = None
        self.q: I = None
        self.o: C = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.z: A = None
        self.o: J = None
        self.y: J = None
        self.u: D = None
        self.s: J = None
        self.x: D = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.x: C = None
        self.t: B = None
        self.u: B = None
        self.p: H = None
        self.s: E = None
        self.z: C = None
        self.w: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.r: D = None
        self.v: A = None
        self.t: G = None
        self.q: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: G = None
        self.r: J = None
        self.t: E = None
        self.v: A = None
        self.o: G = None
        self.u: B = None
        self.y: J = None
        self.z: D = None
        self.w: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: A = None
        self.s: I = None
        self.z: J = None
        self.r: I = None
        self.q: I = None
        self.o: C = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.z: A = None
        self.o: J = None
        self.y: J = None
        self.u: D = None
        self.s: J = None
        self.x: D = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.x: C = None
        self.t: B = None
        self.u: B = None
        self.p: H = None
        self.s: E = None
        self.z: C = None
        self.w: A = None
        self.txt = txt

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

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