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

class B:
    def __init__(self, txt: str):
        self.y: F = None
        self.u: C = None
        self.x: E = None
        self.z: H = None
        self.q: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: I = None
        self.z: E = None
        self.s: E = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: H = None
        self.u: C = None
        self.w: A = None
        self.p: C = None
        self.z: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: C = None
        self.t: I = None
        self.p: H = None
        self.w: H = None
        self.v: A = None
        self.s: B = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: B = None
        self.v: H = None
        self.t: E = None
        self.x: F = None
        self.o: C = None
        self.p: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: C = None
        self.y: C = None
        self.o: D = None
        self.t: B = None
        self.p: F = None
        self.x: C = None
        self.q: D = None
        self.r: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: H = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: F = None
        self.u: C = None
        self.x: E = None
        self.z: H = None
        self.q: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: I = None
        self.z: E = None
        self.s: E = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: H = None
        self.u: C = None
        self.w: A = None
        self.p: C = None
        self.z: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: C = None
        self.t: I = None
        self.p: H = None
        self.w: H = None
        self.v: A = None
        self.s: B = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: B = None
        self.v: H = None
        self.t: E = None
        self.x: F = None
        self.o: C = None
        self.p: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: C = None
        self.y: C = None
        self.o: D = None
        self.t: B = None
        self.p: F = None
        self.x: C = None
        self.q: D = None
        self.r: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: H = None
        self.txt = txt

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

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