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

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.p: I = None
        self.w: E = None
        self.v: H = None
        self.q: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.x: F = None
        self.s: F = None
        self.z: F = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.u: A = None
        self.t: D = None
        self.q: A = None
        self.z: D = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.p: I = None
        self.w: E = None
        self.v: H = None
        self.q: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.x: F = None
        self.s: F = None
        self.z: F = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.u: A = None
        self.t: D = None
        self.q: A = None
        self.z: D = None
        self.txt = txt

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

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