class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.p: B = None
        self.r: F = None
        self.w: A = None
        self.v: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: B = None
        self.u: A = None
        self.x: B = None
        self.p: A = None
        self.t: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: B = None
        self.w: E = None
        self.q: E = None
        self.y: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.z: B = None
        self.t: A = None
        self.v: C = None
        self.q: C = None
        self.u: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: C = None
        self.u: E = None
        self.v: D = None
        self.r: D = None
        self.x: E = None
        self.txt = txt

i = A("i")
m = B("m")
a = C("a")
b = D("b")
c = E("c")
g = F("g")
k = B("k")
f = F("f")
e = A("e")
h = C("h")

i.s = b
i.p = m
i.r = f
i.w = e
i.v = k
m.q = k
m.x = k
m.u = i
m.p = e
m.t = h
a.s = c
a.w = c
a.q = c
a.y = c
a.v = m
b.r = e
c.z = m
c.t = e
c.v = a
c.q = h
c.u = b
g.y = a
g.u = c
g.x = c
g.v = b
g.r = b
k.q = m
k.x = m
k.u = e
k.p = e
k.t = h
f.y = h
f.u = c
f.x = c
f.v = b
f.r = b
e.s = b
e.p = m
e.r = f
e.w = i
e.v = k
h.s = c
h.w = c
h.q = c
h.y = c
h.v = k
assert b.r.v.t.v.txt == "
class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.p: B = None
        self.r: F = None
        self.w: A = None
        self.v: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: B = None
        self.u: A = None
        self.x: B = None
        self.p: A = None
        self.t: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: B = None
        self.w: E = None
        self.q: E = None
        self.y: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.z: B = None
        self.t: A = None
        self.v: C = None
        self.q: C = None
        self.u: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: C = None
        self.u: E = None
        self.v: D = None
        self.r: D = None
        self.x: E = None
        self.txt = txt

i = A("i")
m = B("m")
a = C("a")
b = D("b")
c = E("c")
g = F("g")
k = B("k")
f = F("f")
e = A("e")
h = C("h")

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