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

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: F = None
        self.y: J = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.q: G = None
        self.o: D = None
        self.w: H = None
        self.y: A = None
        self.s: G = None
        self.v: H = None
        self.t: B = None
        self.r: J = None
        self.p: J = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.r: E = None
        self.q: C = None
        self.w: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: C = None
        self.s: I = None
        self.w: E = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: F = None
        self.y: J = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.q: G = None
        self.o: D = None
        self.w: H = None
        self.y: A = None
        self.s: G = None
        self.v: H = None
        self.t: B = None
        self.r: J = None
        self.p: J = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.r: E = None
        self.q: C = None
        self.w: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: C = None
        self.s: I = None
        self.w: E = None
        self.txt = txt

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

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