class A:
    def __init__(self, txt: str):
        self.o: J = None
        self.y: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: J = None
        self.x: D = None
        self.u: A = None
        self.q: E = None
        self.t: A = None
        self.z: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: E = None
        self.s: E = None
        self.t: G = None
        self.o: D = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: I = None
        self.y: A = None
        self.q: I = None
        self.t: D = None
        self.o: G = None
        self.r: C = None
        self.p: I = None
        self.u: C = None
        self.z: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: J = None
        self.u: J = None
        self.z: F = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.q: E = None
        self.r: D = None
        self.y: H = None
        self.txt = txt

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

d.o = f
d.y = c
n.o = f
n.x = j
n.z = j
n.u = d
n.t = d
n.q = c
h.y = n
h.q = c
h.s = c
h.v = c
h.t = k
h.o = j
j.p = g
c.s = l
c.q = l
c.p = l
c.z = l
c.y = d
c.t = j
c.o = k
c.r = h
c.u = h
g.u = c
k.y = f
k.u = f
k.z = g
e.v = l
e.z = l
l.p = k
l.q = k
l.x = g
l.r = g
l.o = h
l.u = n
l.y = e
l.z = e
l.s = d
l.t = d
f.q = c
f.r = j
f.y = e
assert e.v.u.o.y.v.o.y.q.txt == "
class A:
    def __init__(self, txt: str):
        self.o: J = None
        self.y: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: J = None
        self.x: D = None
        self.u: A = None
        self.q: E = None
        self.t: A = None
        self.z: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: E = None
        self.s: E = None
        self.t: G = None
        self.o: D = None
        self.v: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: I = None
        self.y: A = None
        self.q: I = None
        self.t: D = None
        self.o: G = None
        self.r: C = None
        self.p: I = None
        self.u: C = None
        self.z: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: J = None
        self.u: J = None
        self.z: F = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.q: E = None
        self.r: D = None
        self.y: H = None
        self.txt = txt

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

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