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

class B:
    def __init__(self, txt: str):
        self.z: E = None
        self.u: F = None
        self.v: A = None
        self.w: E = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: F = None
        self.z: G = None
        self.q: F = None
        self.s: C = None
        self.v: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.o: E = None
        self.s: B = None
        self.x: A = None
        self.y: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: E = None
        self.v: B = None
        self.y: C = None
        self.o: A = None
        self.z: F = None
        self.txt = txt

e = A("e")
c = B("c")
k = C("k")
h = D("h")
i = E("i")
a = F("a")
g = G("g")
n = D("n")
j = B("j")
m = E("m")

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

class B:
    def __init__(self, txt: str):
        self.z: E = None
        self.u: F = None
        self.v: A = None
        self.w: E = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: F = None
        self.z: G = None
        self.q: F = None
        self.s: C = None
        self.v: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.o: E = None
        self.s: B = None
        self.x: A = None
        self.y: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: E = None
        self.v: B = None
        self.y: C = None
        self.o: A = None
        self.z: F = None
        self.txt = txt

e = A("e")
c = B("c")
k = C("k")
h = D("h")
i = E("i")
a = F("a")
g = G("g")
n = D("n")
j = B("j")
m = E("m")

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