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

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

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.o: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: G = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.r: C = None
        self.w: A = None
        self.v: G = None
        self.x: C = None
        self.q: D = None
        self.t: F = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.o: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: G = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.r: C = None
        self.w: A = None
        self.v: G = None
        self.x: C = None
        self.q: D = None
        self.t: F = None
        self.txt = txt

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

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