class A:
    def __init__(self, txt: str):
        self.x: G = None
        self.v: F = None
        self.z: D = None
        self.u: G = None
        self.o: C = None
        self.t: H = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: H = None
        self.z: F = None
        self.p: H = None
        self.q: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: G = None
        self.z: D = None
        self.v: I = None
        self.p: H = None
        self.y: I = None
        self.r: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: A = None
        self.z: D = None
        self.t: C = None
        self.p: C = None
        self.y: C = None
        self.s: E = None
        self.txt = txt

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

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

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: H = None
        self.z: F = None
        self.p: H = None
        self.q: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: G = None
        self.z: D = None
        self.v: I = None
        self.p: H = None
        self.y: I = None
        self.r: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: A = None
        self.z: D = None
        self.t: C = None
        self.p: C = None
        self.y: C = None
        self.s: E = None
        self.txt = txt

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

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

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

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

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