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

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

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.r: F = None
        self.y: B = None
        self.u: E = None
        self.s: B = None
        self.o: E = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.r: F = None
        self.y: B = None
        self.u: E = None
        self.s: B = None
        self.o: E = None
        self.txt = txt

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

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

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

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

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