class A:
    def __init__(self, txt: str):
        self.z: D = None
        self.w: B = None
        self.u: F = None
        self.p: F = None
        self.q: C = None
        self.v: D = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.x: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: E = None
        self.p: A = None
        self.r: C = None
        self.o: E = None
        self.s: C = None
        self.txt = txt

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

i = A("i")
d = B("d")
e = C("e")
k = D("k")
h = E("h")
a = F("a")
m = E("m")
n = A("n")
b = F("b")

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: E = None
        self.p: A = None
        self.r: C = None
        self.o: E = None
        self.s: C = None
        self.txt = txt

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

i = A("i")
d = B("d")
e = C("e")
k = D("k")
h = E("h")
a = F("a")
m = E("m")
n = A("n")
b = F("b")

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