class A:
    def __init__(self, txt: str):
        self.v: G = None
        self.o: D = None
        self.y: C = None
        self.txt = txt

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

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

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

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

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

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

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

class I:
    def __init__(self, txt: str):
        self.v: J = None
        self.u: F = None
        self.x: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: F = None
        self.p: G = None
        self.v: C = None
        self.t: I = None
        self.txt = txt

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

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

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

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

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

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

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

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

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

class I:
    def __init__(self, txt: str):
        self.v: J = None
        self.u: F = None
        self.x: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: F = None
        self.p: G = None
        self.v: C = None
        self.t: I = None
        self.txt = txt

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

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