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

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

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

class D:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: G = None
        self.v: G = None
        self.x: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: G = None
        self.r: G = None
        self.x: E = None
        self.o: J = None
        self.u: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: C = None
        self.r: C = None
        self.x: H = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: G = None
        self.v: G = None
        self.x: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: B = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: G = None
        self.r: G = None
        self.x: E = None
        self.o: J = None
        self.u: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.w: C = None
        self.r: C = None
        self.x: H = None
        self.txt = txt

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

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