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

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

class C:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: E = None
        self.q: A = None
        self.o: G = None
        self.t: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: H = None
        self.v: D = None
        self.o: G = None
        self.t: I = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.w: I = None
        self.u: A = None
        self.s: G = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: E = None
        self.q: A = None
        self.o: G = None
        self.t: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: H = None
        self.v: D = None
        self.o: G = None
        self.t: I = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.w: I = None
        self.u: A = None
        self.s: G = None
        self.txt = txt

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

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

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

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

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