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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.txt = txt

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.txt = txt

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

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

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

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

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

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