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

class B:
    def __init__(self, txt: str):
        self.x: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: G = None
        self.x: J = None
        self.q: G = None
        self.y: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.w: H = None
        self.o: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: D = None
        self.y: H = None
        self.u: H = None
        self.p: D = None
        self.w: A = None
        self.v: I = None
        self.t: J = None
        self.x: E = None
        self.z: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.o: E = None
        self.v: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: G = None
        self.p: D = None
        self.z: F = None
        self.x: D = None
        self.t: A = None
        self.u: E = None
        self.v: D = None
        self.s: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: E = None
        self.z: G = None
        self.y: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.q: F = None
        self.z: B = None
        self.u: A = None
        self.o: F = None
        self.v: G = None
        self.y: D = None
        self.x: I = None
        self.w: E = None
        self.p: B = None
        self.r: G = None
        self.txt = txt

c = A("c")
h = B("h")
j = C("j")
k = D("k")
g = E("g")
n = F("n")
l = G("l")
i = H("i")
a = I("a")
f = J("f")

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

class B:
    def __init__(self, txt: str):
        self.x: J = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: G = None
        self.x: J = None
        self.q: G = None
        self.y: J = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.w: H = None
        self.o: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: D = None
        self.y: H = None
        self.u: H = None
        self.p: D = None
        self.w: A = None
        self.v: I = None
        self.t: J = None
        self.x: E = None
        self.z: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.o: E = None
        self.v: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: G = None
        self.p: D = None
        self.z: F = None
        self.x: D = None
        self.t: A = None
        self.u: E = None
        self.v: D = None
        self.s: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: E = None
        self.z: G = None
        self.y: H = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.q: F = None
        self.z: B = None
        self.u: A = None
        self.o: F = None
        self.v: G = None
        self.y: D = None
        self.x: I = None
        self.w: E = None
        self.p: B = None
        self.r: G = None
        self.txt = txt

c = A("c")
h = B("h")
j = C("j")
k = D("k")
g = E("g")
n = F("n")
l = G("l")
i = H("i")
a = I("a")
f = J("f")

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