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

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.s: A = None
        self.w: F = None
        self.p: C = None
        self.o: A = None
        self.y: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: D = None
        self.q: A = None
        self.y: E = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.s: C = None
        self.z: E = None
        self.o: C = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.s: A = None
        self.w: F = None
        self.p: C = None
        self.o: A = None
        self.y: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: D = None
        self.q: A = None
        self.y: E = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.w: A = None
        self.s: C = None
        self.z: E = None
        self.o: C = None
        self.txt = txt

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

n.o = h
n.u = c
l.t = g
l.s = f
l.o = f
l.w = j
l.p = k
l.y = c
k.u = c
k.y = c
k.r = h
k.q = f
h.o = c
h.v = g
h.s = g
c.t = k
c.w = m
j.w = n
j.s = k
j.o = k
j.z = c
f.o = g
f.u = c
m.t = g
m.s = f
m.w = j
m.p = k
m.o = n
m.y = c
g.o = c
g.v = h
g.s = h
e.t = h
e.s = n
e.w = j
e.p = k
e.o = f
e.y = c
assert k.r.s.v.v.o.t.y.t.txt == "k"