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

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

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.r: A = None
        self.v: A = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.r: A = None
        self.v: A = None
        self.txt = txt

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

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

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

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

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