class A:
    def __init__(self, txt: str):
        self.s: E = None
        self.q: C = None
        self.y: F = None
        self.w: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: F = None
        self.r: B = None
        self.s: E = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.w: B = None
        self.t: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: F = None
        self.r: B = None
        self.s: E = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.w: B = None
        self.t: B = None
        self.txt = txt

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

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