class A:
    def __init__(self, txt: str):
        self.z: I = None
        self.u: I = None
        self.y: I = None
        self.x: H = None
        self.t: F = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.q: H = None
        self.z: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.u: D = None
        self.q: C = None
        self.o: C = None
        self.txt = txt

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

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.q: H = None
        self.z: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.u: D = None
        self.q: C = None
        self.o: C = None
        self.txt = txt

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

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

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

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