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

class B:
    def __init__(self, txt: str):
        self.p: G = None
        self.z: I = None
        self.t: A = None
        self.u: E = None
        self.x: E = None
        self.y: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: I = None
        self.s: I = None
        self.o: F = None
        self.p: D = None
        self.t: H = None
        self.x: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: I = None
        self.w: E = None
        self.s: F = None
        self.z: I = None
        self.txt = txt

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

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.p: G = None
        self.z: I = None
        self.t: A = None
        self.u: E = None
        self.x: E = None
        self.y: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: I = None
        self.s: I = None
        self.o: F = None
        self.p: D = None
        self.t: H = None
        self.x: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: I = None
        self.w: E = None
        self.s: F = None
        self.z: I = None
        self.txt = txt

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

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

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

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

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

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

g.y = d
j.p = l
j.z = b
j.t = g
j.u = f
j.x = f
j.y = e
d.v = b
d.s = b
d.o = n
d.p = e
d.t = h
d.x = h
e.u = b
e.z = b
e.w = f
e.s = n
f.r = b
f.o = b
f.x = e
f.w = l
n.u = d
l.u = b
h.v = j
h.o = j
h.r = d
h.w = d
h.t = e
h.x = e
h.z = f
h.u = g
h.p = g
b.x = e
b.t = j
a.u = d
assert j.p.u.x.txt == "e"