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

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.y: D = None
        self.txt = txt

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.y: D = None
        self.txt = txt

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

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

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