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

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

class C:
    def __init__(self, txt: str):
        self.y: I = None
        self.v: G = None
        self.u: E = None
        self.txt = txt

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

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

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

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

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

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

b = A("b")
n = B("n")
d = C("d")
h = D("h")
c = E("c")
m = F("m")
g = G("g")
a = H("a")
l = I("l")

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

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

class C:
    def __init__(self, txt: str):
        self.y: I = None
        self.v: G = None
        self.u: E = None
        self.txt = txt

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

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

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

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

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

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

b = A("b")
n = B("n")
d = C("d")
h = D("h")
c = E("c")
m = F("m")
g = G("g")
a = H("a")
l = I("l")

b.o = l
b.r = l
b.q = l
b.v = l
b.x = a
b.w = g
b.z = d
b.y = n
b.s = m
n.q = a
n.p = a
n.y = d
d.y = l
d.v = g
d.u = c
h.s = b
h.o = b
c.s = d
m.t = g
g.s = c
g.u = b
g.p = n
g.v = n
g.y = d
g.r = h
g.t = a
a.u = d
l.w = b
l.r = b
l.t = c
l.o = c
l.v = m
l.s = m
l.u = h
assert a.u.y.u.s.s.t.u.txt == "b"