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

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.t: E = None
        self.r: E = None
        self.s: H = None
        self.x: I = None
        self.u: G = None
        self.z: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: A = None
        self.o: J = None
        self.z: I = None
        self.u: B = None
        self.q: E = None
        self.w: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.o: H = None
        self.y: I = None
        self.u: E = None
        self.z: J = None
        self.t: F = None
        self.r: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: F = None
        self.w: F = None
        self.r: I = None
        self.s: J = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.s: B = None
        self.v: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: F = None
        self.q: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: F = None
        self.o: B = None
        self.r: G = None
        self.txt = txt

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

d = A("d")
i = B("i")
a = C("a")
j = D("j")
n = E("n")
c = F("c")
k = G("k")
f = H("f")
b = I("b")
m = J("m")

d.s = f
d.u = f
d.x = a
d.z = n
d.r = n
d.y = k
d.t = c
d.v = c
i.v = b
i.x = b
i.t = n
i.r = n
i.s = f
i.u = k
i.z = c
a.v = d
a.w = d
a.o = m
a.z = b
a.u = i
a.q = n
j.x = a
j.o = f
j.y = b
j.u = n
j.z = m
j.t = c
j.r = c
n.t = c
n.w = c
n.r = b
n.s = m
c.u = i
c.y = m
k.x = i
k.s = i
k.v = n
f.p = d
f.x = c
f.q = k
b.v = j
b.x = c
b.o = i
b.r = k
m.r = f
assert i.u.s.r.t.y.r.x.u.u.txt == "
class A:
    def __init__(self, txt: str):
        self.s: H = None
        self.x: C = None
        self.z: E = None
        self.r: E = None
        self.y: G = None
        self.u: H = None
        self.t: F = None
        self.v: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: I = None
        self.t: E = None
        self.r: E = None
        self.s: H = None
        self.x: I = None
        self.u: G = None
        self.z: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: A = None
        self.o: J = None
        self.z: I = None
        self.u: B = None
        self.q: E = None
        self.w: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.o: H = None
        self.y: I = None
        self.u: E = None
        self.z: J = None
        self.t: F = None
        self.r: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: F = None
        self.w: F = None
        self.r: I = None
        self.s: J = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.s: B = None
        self.v: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: F = None
        self.q: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: F = None
        self.o: B = None
        self.r: G = None
        self.txt = txt

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

d = A("d")
i = B("i")
a = C("a")
j = D("j")
n = E("n")
c = F("c")
k = G("k")
f = H("f")
b = I("b")
m = J("m")

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