class A:
    def __init__(self, txt: str):
        self.y: D = None
        self.p: D = None
        self.t: E = None
        self.x: C = None
        self.z: D = None
        self.q: A = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.p: D = None
        self.y: A = None
        self.r: D = None
        self.o: E = None
        self.v: E = None
        self.w: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: E = None
        self.s: D = None
        self.t: A = None
        self.w: E = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: E = None
        self.t: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: A = None
        self.x: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.p: D = None
        self.y: A = None
        self.r: D = None
        self.o: E = None
        self.v: E = None
        self.w: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: E = None
        self.s: D = None
        self.t: A = None
        self.w: E = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: E = None
        self.t: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.o: A = None
        self.x: A = None
        self.txt = txt

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

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