class A:
    def __init__(self, txt: str):
        self.y: E = None
        self.q: I = None
        self.r: C = None
        self.p: G = None
        self.u: H = None
        self.o: F = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.q: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.z: G = None
        self.t: E = None
        self.r: H = None
        self.s: D = None
        self.u: G = None
        self.w: G = None
        self.v: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.o: C = None
        self.x: H = None
        self.y: F = None
        self.s: E = None
        self.p: D = None
        self.q: E = None
        self.w: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: C = None
        self.v: D = None
        self.w: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: D = None
        self.u: A = None
        self.t: B = None
        self.x: G = None
        self.v: H = None
        self.s: E = None
        self.p: F = None
        self.w: G = None
        self.txt = txt

c = A("c")
e = B("e")
m = C("m")
g = D("g")
k = E("k")
i = F("i")
a = G("a")
n = H("n")
d = I("d")
f = G("f")

c.y = k
c.q = d
c.r = m
c.p = a
c.u = n
c.o = i
e.q = m
e.t = a
m.t = i
m.q = n
g.u = i
g.v = c
k.r = g
k.x = g
k.p = c
k.z = m
i.o = a
i.z = a
i.u = a
i.t = k
i.r = n
i.s = g
i.v = g
i.w = f
a.u = k
a.s = k
a.q = k
a.w = k
a.o = m
a.x = n
a.y = i
a.p = g
n.o = f
n.r = m
n.v = g
n.w = d
d.z = g
d.u = c
d.t = e
d.x = f
d.v = n
d.s = k
d.p = i
d.w = a
f.u = k
f.s = k
f.q = k
f.w = k
f.o = m
f.x = n
f.y = i
f.p = g
assert c.o.u.p.u.t.z.t.s.u.txt == "
class A:
    def __init__(self, txt: str):
        self.y: E = None
        self.q: I = None
        self.r: C = None
        self.p: G = None
        self.u: H = None
        self.o: F = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.q: H = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.z: G = None
        self.t: E = None
        self.r: H = None
        self.s: D = None
        self.u: G = None
        self.w: G = None
        self.v: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.o: C = None
        self.x: H = None
        self.y: F = None
        self.s: E = None
        self.p: D = None
        self.q: E = None
        self.w: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: C = None
        self.v: D = None
        self.w: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.z: D = None
        self.u: A = None
        self.t: B = None
        self.x: G = None
        self.v: H = None
        self.s: E = None
        self.p: F = None
        self.w: G = None
        self.txt = txt

c = A("c")
e = B("e")
m = C("m")
g = D("g")
k = E("k")
i = F("i")
a = G("a")
n = H("n")
d = I("d")
f = G("f")

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