class A:
    def __init__(self, txt: str):
        self.z: E = None
        self.s: B = None
        self.r: F = None
        self.p: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.u: J = None
        self.t: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: A = None
        self.u: F = None
        self.z: E = None
        self.o: E = None
        self.t: A = None
        self.r: F = None
        self.s: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: H = None
        self.z: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.o: F = None
        self.p: I = None
        self.q: C = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.o: C = None
        self.r: I = None
        self.t: C = None
        self.u: E = None
        self.y: D = None
        self.txt = txt

j = A("j")
g = B("g")
m = C("m")
b = D("b")
a = E("a")
h = F("h")
n = G("n")
i = H("i")
k = I("k")
l = J("l")

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

class B:
    def __init__(self, txt: str):
        self.u: J = None
        self.t: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: A = None
        self.u: F = None
        self.z: E = None
        self.o: E = None
        self.t: A = None
        self.r: F = None
        self.s: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: H = None
        self.z: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.o: F = None
        self.p: I = None
        self.q: C = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.o: C = None
        self.r: I = None
        self.t: C = None
        self.u: E = None
        self.y: D = None
        self.txt = txt

j = A("j")
g = B("g")
m = C("m")
b = D("b")
a = E("a")
h = F("h")
n = G("n")
i = H("i")
k = I("k")
l = J("l")

j.z = a
j.s = g
j.r = h
j.p = m
g.u = l
g.t = n
m.w = g
m.y = j
m.t = j
m.u = h
m.r = h
m.z = a
m.o = a
m.s = a
b.p = m
b.t = j
a.r = i
a.p = h
a.w = h
a.q = n
a.z = b
h.v = i
h.z = g
n.z = l
n.w = i
n.o = b
n.t = b
n.v = g
n.u = j
n.x = m
n.s = a
i.o = h
i.p = k
i.q = m
k.u = n
l.o = m
l.t = m
l.r = k
l.u = a
l.y = b
assert m.o.q.s.q.v.t.x.w.t.t.txt == "b"