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

class B:
    def __init__(self, txt: str):
        self.s: I = None
        self.v: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.x: C = None
        self.u: G = None
        self.s: E = None
        self.z: F = None
        self.v: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.s: D = None
        self.y: C = None
        self.v: B = None
        self.x: D = None
        self.w: J = None
        self.z: F = None
        self.u: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: J = None
        self.t: E = None
        self.o: B = None
        self.s: J = None
        self.q: J = None
        self.v: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.y: D = None
        self.txt = txt

f = A("f")
b = B("b")
j = C("j")
c = D("c")
h = E("h")
m = F("m")
g = G("g")
k = H("k")
e = I("e")
l = J("l")

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

class B:
    def __init__(self, txt: str):
        self.s: I = None
        self.v: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.x: C = None
        self.u: G = None
        self.s: E = None
        self.z: F = None
        self.v: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.s: D = None
        self.y: C = None
        self.v: B = None
        self.x: D = None
        self.w: J = None
        self.z: F = None
        self.u: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: J = None
        self.t: E = None
        self.o: B = None
        self.s: J = None
        self.q: J = None
        self.v: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.y: D = None
        self.txt = txt

f = A("f")
b = B("b")
j = C("j")
c = D("c")
h = E("h")
m = F("m")
g = G("g")
k = H("k")
e = I("e")
l = J("l")

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