class A:
    def __init__(self, txt: str):
        self.v: E = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.u: A = None
        self.z: A = None
        self.t: F = None
        self.q: B = None
        self.y: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.s: B = None
        self.x: F = None
        self.z: C = None
        self.r: D = None
        self.txt = txt

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

b.v = c
k.s = n
k.r = n
k.z = b
k.v = j
k.x = e
k.y = a
a.z = n
a.w = d
d.x = l
d.u = b
d.z = b
d.t = n
d.q = k
d.y = a
f.y = n
f.w = a
n.w = b
l.u = a
l.z = a
l.s = e
l.x = n
l.r = d
j.y = n
j.w = a
c.y = n
c.w = a
e.s = n
e.r = n
e.z = b
e.v = c
e.x = k
e.y = a
assert a.z.w.v.y.w.v.y.txt == "
class A:
    def __init__(self, txt: str):
        self.v: E = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.u: A = None
        self.z: A = None
        self.t: F = None
        self.q: B = None
        self.y: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.s: B = None
        self.x: F = None
        self.z: C = None
        self.r: D = None
        self.txt = txt

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

b.v = c
k.s = n
k.r = n
k.z = b
k.v = j
k.x = e
k.y = a
a.z = n
a.w = d
d.x = l
d.u = b
d.z = b
d.t = n
d.q = k
d.y = a
f.y = n
f.w = a
n.w = b
l.u = a
l.z = a
l.s = e
l.x = n
l.r = d
j.y = n
j.w = a
c.y = n
c.w = a
e.s = n
e.r = n
e.z = b
e.v = c
e.x = k
e.y = a
assert a.z.w.v.y.w.v.y.txt == "n"