class A:
    def __init__(self, txt: str):
        self.o: C = None
        self.x: H = None
        self.r: E = None
        self.p: C = None
        self.s: C = None
        self.q: J = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.u: I = None
        self.o: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.p: H = None
        self.x: A = None
        self.z: G = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: B = None
        self.t: B = None
        self.q: B = None
        self.z: A = None
        self.s: H = None
        self.r: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: G = None
        self.r: E = None
        self.v: J = None
        self.y: E = None
        self.u: G = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.u: I = None
        self.o: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.p: H = None
        self.x: A = None
        self.z: G = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: B = None
        self.t: B = None
        self.q: B = None
        self.z: A = None
        self.s: H = None
        self.r: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: G = None
        self.r: E = None
        self.v: J = None
        self.y: E = None
        self.u: G = None
        self.txt = txt

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

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

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

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