class A:
    def __init__(self, txt: str):
        self.z: C = None
        self.y: G = None
        self.r: F = None
        self.q: E = None
        self.w: H = None
        self.p: B = None
        self.t: C = None
        self.o: E = None
        self.u: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.s: G = None
        self.u: G = None
        self.y: D = None
        self.w: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: H = None
        self.q: H = None
        self.p: G = None
        self.o: G = None
        self.t: B = None
        self.x: C = None
        self.s: A = None
        self.u: C = None
        self.y: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: I = None
        self.t: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: C = None
        self.w: C = None
        self.z: H = None
        self.q: D = None
        self.r: C = None
        self.p: E = None
        self.txt = txt

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

i = A("i")
n = B("n")
m = C("m")
j = D("j")
f = E("f")
e = F("e")
d = G("d")
h = H("h")
l = I("l")
c = H("c")

i.z = m
i.t = m
i.u = m
i.y = d
i.r = e
i.q = f
i.o = f
i.w = c
i.p = n
n.v = l
n.s = d
n.u = d
n.y = j
n.w = m
m.y = n
j.t = d
f.u = i
f.o = m
f.t = m
f.y = c
f.p = d
e.r = c
e.q = c
e.p = d
e.o = d
e.t = n
e.x = m
e.u = m
e.s = i
e.y = j
d.s = l
d.t = f
h.s = m
h.w = m
h.r = m
h.z = c
h.q = j
h.p = f
l.w = e
c.s = m
c.w = m
c.r = m
c.z = h
c.q = j
c.p = f
assert d.s.w.u.y.w.y.txt == "
class A:
    def __init__(self, txt: str):
        self.z: C = None
        self.y: G = None
        self.r: F = None
        self.q: E = None
        self.w: H = None
        self.p: B = None
        self.t: C = None
        self.o: E = None
        self.u: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.s: G = None
        self.u: G = None
        self.y: D = None
        self.w: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: H = None
        self.q: H = None
        self.p: G = None
        self.o: G = None
        self.t: B = None
        self.x: C = None
        self.s: A = None
        self.u: C = None
        self.y: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: I = None
        self.t: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: C = None
        self.w: C = None
        self.z: H = None
        self.q: D = None
        self.r: C = None
        self.p: E = None
        self.txt = txt

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

i = A("i")
n = B("n")
m = C("m")
j = D("j")
f = E("f")
e = F("e")
d = G("d")
h = H("h")
l = I("l")
c = H("c")

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