class A:
    def __init__(self, txt: str):
        self.q: F = None
        self.t: D = None
        self.w: C = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: F = None
        self.z: B = None
        self.y: F = None
        self.o: C = None
        self.p: F = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.p: A = None
        self.v: A = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.q: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: F = None
        self.z: B = None
        self.y: F = None
        self.o: C = None
        self.p: F = None
        self.t: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.p: A = None
        self.v: A = None
        self.txt = txt

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

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