class A:
    def __init__(self, txt: str):
        self.y: E = None
        self.t: E = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.x: D = None
        self.p: D = None
        self.t: D = None
        self.q: D = None
        self.txt = txt

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

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

d = A("d")
i = B("i")
f = C("f")
k = D("k")
b = E("b")
e = F("e")
l = D("l")
c = E("c")
n = F("n")
j = E("j")

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: D = None
        self.p: D = None
        self.t: D = None
        self.q: D = None
        self.txt = txt

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

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

d = A("d")
i = B("i")
f = C("f")
k = D("k")
b = E("b")
e = F("e")
l = D("l")
c = E("c")
n = F("n")
j = E("j")

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