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

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

class C:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.v: B = None
        self.w: C = None
        self.y: F = None
        self.r: A = None
        self.u: F = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.v: B = None
        self.w: C = None
        self.y: F = None
        self.r: A = None
        self.u: F = None
        self.txt = txt

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

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