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

class B:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: C = None
        self.o: E = None
        self.p: A = None
        self.y: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.y: C = None
        self.o: E = None
        self.txt = txt

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

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

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

l.s = a
l.o = n
l.v = n
l.t = m
l.z = b
b.p = m
b.t = e
m.u = g
m.o = d
m.p = l
m.y = n
e.s = f
e.y = g
e.o = d
d.y = a
d.s = a
d.o = b
d.u = e
a.z = d
a.s = e
a.v = b
g.u = m
g.o = f
g.p = n
g.y = n
f.y = a
f.s = a
f.o = b
f.u = e
n.s = a
n.o = l
n.v = l
n.t = g
n.z = b
assert b.p.u.u.y.txt == "
class A:
    def __init__(self, txt: str):
        self.s: F = None
        self.o: A = None
        self.v: A = None
        self.t: C = None
        self.z: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.p: C = None
        self.t: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: C = None
        self.o: E = None
        self.p: A = None
        self.y: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.y: C = None
        self.o: E = None
        self.txt = txt

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

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

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

l.s = a
l.o = n
l.v = n
l.t = m
l.z = b
b.p = m
b.t = e
m.u = g
m.o = d
m.p = l
m.y = n
e.s = f
e.y = g
e.o = d
d.y = a
d.s = a
d.o = b
d.u = e
a.z = d
a.s = e
a.v = b
g.u = m
g.o = f
g.p = n
g.y = n
f.y = a
f.s = a
f.o = b
f.u = e
n.s = a
n.o = l
n.v = l
n.t = g
n.z = b
assert b.p.u.u.y.txt == "n"