class A:
    def __init__(self, txt: str):
        self.x: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: G = None
        self.r: F = None
        self.q: I = None
        self.y: C = None
        self.z: H = None
        self.s: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: G = None
        self.u: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.q: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.r: A = None
        self.p: E = None
        self.w: A = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.w: G = None
        self.r: F = None
        self.q: I = None
        self.y: C = None
        self.z: H = None
        self.s: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: G = None
        self.u: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.q: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.r: A = None
        self.p: E = None
        self.w: A = None
        self.txt = txt

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

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

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

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