class A:
    def __init__(self, txt: str):
        self.y: F = None
        self.q: J = None
        self.s: F = None
        self.u: F = None
        self.p: E = None
        self.t: F = None
        self.o: E = None
        self.r: F = None
        self.x: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: J = None
        self.w: C = None
        self.q: H = None
        self.t: I = None
        self.v: A = None
        self.z: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: D = None
        self.t: F = None
        self.y: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: H = None
        self.v: F = None
        self.u: G = None
        self.x: J = None
        self.o: B = None
        self.t: H = None
        self.s: B = None
        self.q: C = None
        self.z: C = None
        self.y: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: J = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.y: D = None
        self.u: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: C = None
        self.z: A = None
        self.v: E = None
        self.r: E = None
        self.u: J = None
        self.q: H = None
        self.y: F = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.o: J = None
        self.w: C = None
        self.q: H = None
        self.t: I = None
        self.v: A = None
        self.z: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: D = None
        self.t: F = None
        self.y: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: H = None
        self.v: F = None
        self.u: G = None
        self.x: J = None
        self.o: B = None
        self.t: H = None
        self.s: B = None
        self.q: C = None
        self.z: C = None
        self.y: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: A = None
        self.p: J = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.y: D = None
        self.u: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: C = None
        self.z: A = None
        self.v: E = None
        self.r: E = None
        self.u: J = None
        self.q: H = None
        self.y: F = None
        self.txt = txt

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

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

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