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

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

class C:
    def __init__(self, txt: str):
        self.o: A = None
        self.x: A = None
        self.s: D = None
        self.t: D = None
        self.w: D = None
        self.txt = txt

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

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

i = A("i")
e = B("e")
k = C("k")
c = D("c")
n = E("n")
f = E("f")
b = A("b")
j = A("j")
m = E("m")

i.y = e
i.s = e
i.r = c
e.o = j
k.o = j
k.x = b
k.s = c
k.t = c
k.w = c
c.t = j
c.p = e
n.y = e
n.q = e
n.o = c
n.u = j
n.w = f
f.y = e
f.q = e
f.o = c
f.u = i
f.w = m
b.y = e
b.s = e
b.r = c
j.y = e
j.s = e
j.r = c
m.y = e
m.q = e
m.o = c
m.u = b
m.w = n
assert c.t.y.o.r.t.r.p.o.s.txt == "
class A:
    def __init__(self, txt: str):
        self.y: B = None
        self.r: D = None
        self.s: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.o: A = None
        self.x: A = None
        self.s: D = None
        self.t: D = None
        self.w: D = None
        self.txt = txt

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

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

i = A("i")
e = B("e")
k = C("k")
c = D("c")
n = E("n")
f = E("f")
b = A("b")
j = A("j")
m = E("m")

i.y = e
i.s = e
i.r = c
e.o = j
k.o = j
k.x = b
k.s = c
k.t = c
k.w = c
c.t = j
c.p = e
n.y = e
n.q = e
n.o = c
n.u = j
n.w = f
f.y = e
f.q = e
f.o = c
f.u = i
f.w = m
b.y = e
b.s = e
b.r = c
j.y = e
j.s = e
j.r = c
m.y = e
m.q = e
m.o = c
m.u = b
m.w = n
assert c.t.y.o.r.t.r.p.o.s.txt == "e"