class A:
    def __init__(self, txt: str):
        self.w: B = None
        self.v: B = None
        self.t: E = None
        self.r: C = None
        self.q: B = None
        self.y: G = None
        self.s: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.v: C = None
        self.q: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: G = None
        self.z: B = None
        self.p: D = None
        self.u: D = None
        self.w: D = None
        self.t: A = None
        self.s: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.o: B = None
        self.u: C = None
        self.x: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.v: C = None
        self.q: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: G = None
        self.z: B = None
        self.p: D = None
        self.u: D = None
        self.w: D = None
        self.t: A = None
        self.s: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.o: B = None
        self.u: C = None
        self.x: A = None
        self.txt = txt

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

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