class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.p: F = None
        self.u: G = None
        self.y: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.y: E = None
        self.p: A = None
        self.v: F = None
        self.t: G = None
        self.w: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: G = None
        self.t: D = None
        self.x: E = None
        self.z: G = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.s: A = None
        self.txt = txt

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

h = A("h")
j = B("j")
d = C("d")
i = D("i")
c = E("c")
k = F("k")
g = G("g")
f = F("f")
a = G("a")
l = F("l")

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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.y: E = None
        self.p: A = None
        self.v: F = None
        self.t: G = None
        self.w: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: G = None
        self.t: D = None
        self.x: E = None
        self.z: G = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.s: A = None
        self.txt = txt

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

h = A("h")
j = B("j")
d = C("d")
i = D("i")
c = E("c")
k = F("k")
g = G("g")
f = F("f")
a = G("a")
l = F("l")

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