class A:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.u: A = None
        self.o: F = None
        self.x: F = None
        self.r: J = None
        self.s: F = None
        self.q: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.w: C = None
        self.q: B = None
        self.z: E = None
        self.y: C = None
        self.p: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: H = None
        self.v: E = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.o: C = None
        self.w: F = None
        self.y: H = None
        self.u: F = None
        self.p: B = None
        self.t: F = None
        self.x: H = None
        self.v: C = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.v: B = None
        self.u: A = None
        self.o: F = None
        self.x: F = None
        self.r: J = None
        self.s: F = None
        self.q: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.w: C = None
        self.q: B = None
        self.z: E = None
        self.y: C = None
        self.p: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.q: H = None
        self.v: E = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.o: C = None
        self.w: F = None
        self.y: H = None
        self.u: F = None
        self.p: B = None
        self.t: F = None
        self.x: H = None
        self.v: C = None
        self.txt = txt

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

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