class A:
    def __init__(self, txt: str):
        self.q: I = None
        self.s: G = None
        self.x: E = None
        self.u: F = None
        self.v: C = None
        self.z: C = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: I = None
        self.r: A = None
        self.x: C = None
        self.u: B = None
        self.z: A = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: F = None
        self.w: A = None
        self.r: B = None
        self.o: I = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: I = None
        self.r: A = None
        self.x: C = None
        self.u: B = None
        self.z: A = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: F = None
        self.w: A = None
        self.r: B = None
        self.o: I = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

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

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

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