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

class B:
    def __init__(self, txt: str):
        self.z: D = None
        self.w: A = None
        self.x: D = None
        self.r: F = None
        self.t: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.v: B = None
        self.u: A = None
        self.p: D = None
        self.x: D = None
        self.q: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: B = None
        self.o: A = None
        self.x: F = None
        self.r: D = None
        self.y: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.u: C = None
        self.txt = txt

a = A("a")
e = B("e")
i = C("i")
k = D("k")
b = E("b")
l = F("l")
j = C("j")
n = D("n")
c = D("c")

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

class B:
    def __init__(self, txt: str):
        self.z: D = None
        self.w: A = None
        self.x: D = None
        self.r: F = None
        self.t: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: B = None
        self.v: B = None
        self.u: A = None
        self.p: D = None
        self.x: D = None
        self.q: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: B = None
        self.o: A = None
        self.x: F = None
        self.r: D = None
        self.y: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.u: C = None
        self.txt = txt

a = A("a")
e = B("e")
i = C("i")
k = D("k")
b = E("b")
l = F("l")
j = C("j")
n = D("n")
c = D("c")

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