class A:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: F = None
        self.u: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.q: B = None
        self.u: D = None
        self.z: A = None
        self.o: H = None
        self.y: B = None
        self.r: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.u: I = None
        self.y: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: B = None
        self.t: B = None
        self.y: I = None
        self.r: E = None
        self.x: I = None
        self.q: A = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: E = None
        self.u: G = None
        self.x: F = None
        self.z: G = None
        self.p: B = None
        self.r: A = None
        self.w: D = None
        self.txt = txt

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

b = A("b")
c = B("c")
e = C("e")
g = D("g")
f = E("f")
k = F("k")
n = G("n")
l = H("l")
a = I("a")

b.z = f
b.o = k
b.u = a
c.r = f
c.y = a
e.w = c
e.q = c
e.y = c
e.u = g
e.z = b
e.o = l
e.r = l
g.z = c
g.u = a
g.y = l
f.u = k
f.z = k
f.r = b
k.v = c
k.t = c
k.y = a
k.x = a
k.r = f
k.q = b
n.y = e
l.y = c
l.p = c
l.q = f
l.u = n
l.z = n
l.x = k
l.r = b
l.w = g
a.x = e
a.u = e
a.s = c
a.w = b
a.o = b
a.v = g
assert c.r.r.z.z.t.y.txt == "
class A:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: F = None
        self.u: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.q: B = None
        self.u: D = None
        self.z: A = None
        self.o: H = None
        self.y: B = None
        self.r: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.u: I = None
        self.y: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: B = None
        self.t: B = None
        self.y: I = None
        self.r: E = None
        self.x: I = None
        self.q: A = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: E = None
        self.u: G = None
        self.x: F = None
        self.z: G = None
        self.p: B = None
        self.r: A = None
        self.w: D = None
        self.txt = txt

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

b = A("b")
c = B("c")
e = C("e")
g = D("g")
f = E("f")
k = F("k")
n = G("n")
l = H("l")
a = I("a")

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