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

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

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

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

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

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

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

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

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

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

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

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

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

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

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