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

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

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

class D:
    def __init__(self, txt: str):
        self.t: E = None
        self.z: F = None
        self.x: A = None
        self.o: D = None
        self.s: F = None
        self.q: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: A = None
        self.p: E = None
        self.t: C = None
        self.w: A = None
        self.s: B = None
        self.txt = txt

c = A("c")
e = B("e")
h = C("h")
g = D("g")
i = E("i")
j = F("j")
f = D("f")
d = E("d")
l = C("l")

c.u = e
c.q = h
c.p = g
e.v = c
h.y = d
h.r = j
h.q = f
h.v = i
g.t = i
g.z = j
g.s = j
g.q = j
g.x = c
g.o = f
i.u = d
i.o = e
i.x = g
i.z = g
j.v = i
j.p = i
j.u = c
j.w = c
j.t = l
j.s = e
f.t = i
f.z = j
f.s = j
f.q = j
f.x = c
f.o = g
d.u = i
d.o = e
d.x = g
d.z = g
l.y = i
l.r = j
l.q = g
l.v = d
assert l.y.x.t.o.v.p.t.o.txt == "
class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.q: C = None
        self.p: D = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.t: E = None
        self.z: F = None
        self.x: A = None
        self.o: D = None
        self.s: F = None
        self.q: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: A = None
        self.p: E = None
        self.t: C = None
        self.w: A = None
        self.s: B = None
        self.txt = txt

c = A("c")
e = B("e")
h = C("h")
g = D("g")
i = E("i")
j = F("j")
f = D("f")
d = E("d")
l = C("l")

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