class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: B = None
        self.r: D = None
        self.p: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.w: C = None
        self.v: A = None
        self.p: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: B = None
        self.z: C = None
        self.s: C = None
        self.v: A = None
        self.txt = txt

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

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

g = A("g")
i = B("i")
a = C("a")
l = D("l")
e = E("e")
j = F("j")
c = F("c")
n = E("n")
f = B("f")
m = C("m")

g.u = f
g.s = j
i.x = g
i.o = f
i.p = f
i.r = l
a.y = l
a.w = m
a.p = m
a.v = g
l.p = i
l.z = m
l.s = m
l.v = g
e.s = l
e.u = m
e.p = j
j.y = m
j.r = m
c.y = m
c.r = a
n.s = l
n.u = a
n.p = c
f.x = g
f.o = i
f.p = i
f.r = l
m.y = l
m.w = a
m.p = a
m.v = g
assert n.p.y.y.txt == "
class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.s: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: B = None
        self.r: D = None
        self.p: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: D = None
        self.w: C = None
        self.v: A = None
        self.p: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: B = None
        self.z: C = None
        self.s: C = None
        self.v: A = None
        self.txt = txt

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

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

g = A("g")
i = B("i")
a = C("a")
l = D("l")
e = E("e")
j = F("j")
c = F("c")
n = E("n")
f = B("f")
m = C("m")

g.u = f
g.s = j
i.x = g
i.o = f
i.p = f
i.r = l
a.y = l
a.w = m
a.p = m
a.v = g
l.p = i
l.z = m
l.s = m
l.v = g
e.s = l
e.u = m
e.p = j
j.y = m
j.r = m
c.y = m
c.r = a
n.s = l
n.u = a
n.p = c
f.x = g
f.o = i
f.p = i
f.r = l
m.y = l
m.w = a
m.p = a
m.v = g
assert n.p.y.y.txt == "l"