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

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

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.o: B = None
        self.r: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: G = None
        self.z: E = None
        self.r: E = None
        self.u: A = None
        self.p: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: D = None
        self.t: D = None
        self.o: A = None
        self.u: A = None
        self.s: F = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.r: E = None
        self.v: E = None
        self.s: I = None
        self.u: C = None
        self.q: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: B = None
        self.u: H = None
        self.z: A = None
        self.p: G = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.o: B = None
        self.r: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: G = None
        self.z: E = None
        self.r: E = None
        self.u: A = None
        self.p: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: D = None
        self.t: D = None
        self.o: A = None
        self.u: A = None
        self.s: F = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.r: E = None
        self.v: E = None
        self.s: I = None
        self.u: C = None
        self.q: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: B = None
        self.u: H = None
        self.z: A = None
        self.p: G = None
        self.txt = txt

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

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