class A:
    def __init__(self, txt: str):
        self.x: J = None
        self.u: I = None
        self.w: E = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: J = None
        self.p: B = None
        self.r: B = None
        self.s: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.w: H = None
        self.t: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: J = None
        self.q: I = None
        self.v: C = None
        self.r: I = None
        self.o: G = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.x: H = None
        self.z: C = None
        self.y: H = None
        self.q: A = None
        self.t: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: B = None
        self.z: B = None
        self.q: E = None
        self.r: C = None
        self.t: A = None
        self.v: D = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: J = None
        self.p: B = None
        self.r: B = None
        self.s: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.w: H = None
        self.t: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: J = None
        self.q: I = None
        self.v: C = None
        self.r: I = None
        self.o: G = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.r: H = None
        self.x: H = None
        self.z: C = None
        self.y: H = None
        self.q: A = None
        self.t: B = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.x: B = None
        self.z: B = None
        self.q: E = None
        self.r: C = None
        self.t: A = None
        self.v: D = None
        self.txt = txt

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

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

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