class A:
    def __init__(self, txt: str):
        self.o: E = None
        self.t: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.w: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: H = None
        self.v: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.v: D = None
        self.r: J = None
        self.p: J = None
        self.u: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: A = None
        self.r: G = None
        self.v: G = None
        self.z: C = None
        self.w: E = None
        self.q: C = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: D = None
        self.y: F = None
        self.r: F = None
        self.t: G = None
        self.w: H = None
        self.u: J = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.w: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: H = None
        self.v: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.v: D = None
        self.r: J = None
        self.p: J = None
        self.u: J = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: A = None
        self.r: G = None
        self.v: G = None
        self.z: C = None
        self.w: E = None
        self.q: C = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: D = None
        self.y: F = None
        self.r: F = None
        self.t: G = None
        self.w: H = None
        self.u: J = None
        self.txt = txt

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

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

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