class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.r: B = None
        self.w: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: C = None
        self.x: A = None
        self.z: D = None
        self.s: A = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.o: D = None
        self.p: E = None
        self.s: B = None
        self.u: B = None
        self.q: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: D = None
        self.v: C = None
        self.t: B = None
        self.s: E = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.t: C = None
        self.x: A = None
        self.z: D = None
        self.s: A = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.o: D = None
        self.p: E = None
        self.s: B = None
        self.u: B = None
        self.q: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: D = None
        self.v: C = None
        self.t: B = None
        self.s: E = None
        self.txt = txt

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

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