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

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: I = None
        self.w: F = None
        self.txt = txt

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

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

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

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

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: I = None
        self.w: F = None
        self.txt = txt

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

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

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

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