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

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

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

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

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

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

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

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

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

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

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

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

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

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

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