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

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.s: H = None
        self.y: E = None
        self.v: C = None
        self.r: I = None
        self.p: C = None
        self.x: C = None
        self.t: C = None
        self.o: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: I = None
        self.r: E = None
        self.p: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.t: G = None
        self.z: I = None
        self.s: H = None
        self.x: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: I = None
        self.o: I = None
        self.s: A = None
        self.w: H = None
        self.t: I = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: H = None
        self.r: B = None
        self.y: F = None
        self.v: C = None
        self.s: H = None
        self.o: B = None
        self.t: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: C = None
        self.txt = txt

b = A("b")
e = B("e")
f = C("f")
a = D("a")
k = E("k")
h = F("h")
i = G("i")
l = H("l")
m = I("m")
c = H("c")

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

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.s: H = None
        self.y: E = None
        self.v: C = None
        self.r: I = None
        self.p: C = None
        self.x: C = None
        self.t: C = None
        self.o: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: I = None
        self.r: E = None
        self.p: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.t: G = None
        self.z: I = None
        self.s: H = None
        self.x: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: I = None
        self.o: I = None
        self.s: A = None
        self.w: H = None
        self.t: I = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: H = None
        self.r: B = None
        self.y: F = None
        self.v: C = None
        self.s: H = None
        self.o: B = None
        self.t: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: C = None
        self.txt = txt

b = A("b")
e = B("e")
f = C("f")
a = D("a")
k = E("k")
h = F("h")
i = G("i")
l = H("l")
m = I("m")
c = H("c")

b.z = e
b.s = e
b.u = h
e.w = k
e.y = k
e.o = k
e.s = l
e.v = f
e.p = f
e.x = f
e.t = f
e.r = m
f.s = m
f.p = m
f.r = k
a.v = k
a.t = i
a.z = m
a.s = c
a.x = b
k.u = i
k.w = h
k.t = h
k.v = b
k.r = b
h.v = m
h.o = m
h.t = m
h.s = b
h.w = l
i.z = c
i.s = c
i.r = e
i.o = e
i.t = e
i.y = h
i.v = f
l.t = c
m.s = f
c.t = l
assert e.s.t.t.t.t.t.t.t.txt == "c"