class A:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: I = None
        self.o: H = None
        self.s: D = None
        self.q: H = None
        self.z: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.o: I = None
        self.p: B = None
        self.t: G = None
        self.y: C = None
        self.s: I = None
        self.x: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.s: F = None
        self.p: F = None
        self.u: I = None
        self.z: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.t: H = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: A = None
        self.v: G = None
        self.z: A = None
        self.w: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: A = None
        self.v: H = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.w: I = None
        self.o: H = None
        self.s: D = None
        self.q: H = None
        self.z: H = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.o: I = None
        self.p: B = None
        self.t: G = None
        self.y: C = None
        self.s: I = None
        self.x: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: G = None
        self.s: F = None
        self.p: F = None
        self.u: I = None
        self.z: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.t: H = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: A = None
        self.v: G = None
        self.z: A = None
        self.w: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: A = None
        self.v: H = None
        self.txt = txt

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

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