class A:
    def __init__(self, txt: str):
        self.v: D = None
        self.s: J = None
        self.t: J = None
        self.p: D = None
        self.u: H = None
        self.y: D = None
        self.w: I = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.x: E = None
        self.u: B = None
        self.s: H = None
        self.t: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: I = None
        self.w: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.q: J = None
        self.x: D = None
        self.t: J = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.t: F = None
        self.q: C = None
        self.r: A = None
        self.x: H = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.x: E = None
        self.u: B = None
        self.s: H = None
        self.t: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: I = None
        self.w: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.q: J = None
        self.x: D = None
        self.t: J = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.t: F = None
        self.q: C = None
        self.r: A = None
        self.x: H = None
        self.txt = txt

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

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