class A:
    def __init__(self, txt: str):
        self.x: D = None
        self.s: B = None
        self.v: I = None
        self.u: G = None
        self.q: B = None
        self.p: E = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: G = None
        self.v: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.x: F = None
        self.o: I = None
        self.p: I = None
        self.q: D = None
        self.y: D = None
        self.t: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: C = None
        self.o: H = None
        self.x: E = None
        self.z: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: H = None
        self.y: D = None
        self.x: E = None
        self.v: F = None
        self.o: E = None
        self.r: E = None
        self.q: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.x: G = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: G = None
        self.v: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.x: F = None
        self.o: I = None
        self.p: I = None
        self.q: D = None
        self.y: D = None
        self.t: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: C = None
        self.o: H = None
        self.x: E = None
        self.z: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: H = None
        self.y: D = None
        self.x: E = None
        self.v: F = None
        self.o: E = None
        self.r: E = None
        self.q: B = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.x: G = None
        self.txt = txt

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

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