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

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

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

class D:
    def __init__(self, txt: str):
        self.x: F = None
        self.s: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: D = None
        self.r: G = None
        self.w: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.z: C = None
        self.r: I = None
        self.v: D = None
        self.o: A = None
        self.s: D = None
        self.x: C = None
        self.w: B = None
        self.txt = txt

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

j = A("j")
n = B("n")
m = C("m")
k = D("k")
i = E("i")
b = F("b")
h = G("h")
a = H("a")
f = I("f")
l = F("l")

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: F = None
        self.s: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: D = None
        self.r: G = None
        self.w: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.z: C = None
        self.r: I = None
        self.v: D = None
        self.o: A = None
        self.s: D = None
        self.x: C = None
        self.w: B = None
        self.txt = txt

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

j = A("j")
n = B("n")
m = C("m")
k = D("k")
i = E("i")
b = F("b")
h = G("h")
a = H("a")
f = I("f")
l = F("l")

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