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

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: A = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.r: A = None
        self.v: B = None
        self.x: A = None
        self.p: B = None
        self.s: G = None
        self.o: F = None
        self.z: D = None
        self.txt = txt

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

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

l.u = i
l.x = d
b.t = f
b.y = d
b.r = h
b.p = m
b.v = i
b.o = k
b.z = l
k.z = d
k.x = d
k.r = i
k.o = l
k.u = h
k.p = m
m.s = i
m.x = d
i.t = l
d.y = h
e.v = h
e.s = l
e.q = k
f.r = l
f.x = l
f.v = b
f.p = b
f.s = e
f.o = d
f.z = m
h.v = e
h.x = b
h.o = b
h.s = b
h.p = b
h.z = m
h.r = m
h.q = m
h.w = l
assert l.u.t.u.t.x.y.w.u.t.txt == "
class A:
    def __init__(self, txt: str):
        self.u: E = None
        self.x: F = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: A = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.r: A = None
        self.v: B = None
        self.x: A = None
        self.p: B = None
        self.s: G = None
        self.o: F = None
        self.z: D = None
        self.txt = txt

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

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

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