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

class B:
    def __init__(self, txt: str):
        self.y: I = None
        self.u: G = None
        self.p: D = None
        self.r: D = None
        self.s: D = None
        self.w: A = None
        self.o: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.t: D = None
        self.r: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: G = None
        self.z: H = None
        self.w: E = None
        self.s: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: B = None
        self.u: C = None
        self.o: E = None
        self.z: E = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: I = None
        self.u: G = None
        self.p: D = None
        self.r: D = None
        self.s: D = None
        self.w: A = None
        self.o: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.t: D = None
        self.r: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: G = None
        self.z: H = None
        self.w: E = None
        self.s: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: B = None
        self.u: C = None
        self.o: E = None
        self.z: E = None
        self.txt = txt

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

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

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