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

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.o: C = None
        self.x: D = None
        self.s: H = None
        self.u: B = None
        self.z: D = None
        self.w: F = None
        self.r: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: I = None
        self.w: G = None
        self.x: H = None
        self.y: A = None
        self.p: B = None
        self.r: G = None
        self.q: A = None
        self.t: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.u: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: C = None
        self.q: D = None
        self.o: G = None
        self.s: B = None
        self.p: E = None
        self.t: C = None
        self.y: F = None
        self.z: B = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.o: C = None
        self.x: D = None
        self.s: H = None
        self.u: B = None
        self.z: D = None
        self.w: F = None
        self.r: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: I = None
        self.w: G = None
        self.x: H = None
        self.y: A = None
        self.p: B = None
        self.r: G = None
        self.q: A = None
        self.t: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.u: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: C = None
        self.q: D = None
        self.o: G = None
        self.s: B = None
        self.p: E = None
        self.t: C = None
        self.y: F = None
        self.z: B = None
        self.txt = txt

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

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