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

class B:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: I = None
        self.s: D = None
        self.w: I = None
        self.x: J = None
        self.o: I = None
        self.y: C = None
        self.u: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: J = None
        self.z: H = None
        self.u: F = None
        self.t: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.z: I = None
        self.r: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: D = None
        self.q: B = None
        self.t: C = None
        self.r: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: C = None
        self.t: A = None
        self.r: I = None
        self.q: J = None
        self.w: D = None
        self.x: I = None
        self.p: D = None
        self.u: E = None
        self.z: G = None
        self.v: I = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.o: A = None
        self.w: F = None
        self.q: G = None
        self.p: F = None
        self.s: A = None
        self.z: C = None
        self.v: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: H = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: I = None
        self.s: D = None
        self.w: I = None
        self.x: J = None
        self.o: I = None
        self.y: C = None
        self.u: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: J = None
        self.z: H = None
        self.u: F = None
        self.t: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.z: I = None
        self.r: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: D = None
        self.q: B = None
        self.t: C = None
        self.r: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: C = None
        self.t: A = None
        self.r: I = None
        self.q: J = None
        self.w: D = None
        self.x: I = None
        self.p: D = None
        self.u: E = None
        self.z: G = None
        self.v: I = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.o: A = None
        self.w: F = None
        self.q: G = None
        self.p: F = None
        self.s: A = None
        self.z: C = None
        self.v: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: H = None
        self.txt = txt

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

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