class A:
    def __init__(self, txt: str):
        self.u: E = None
        self.x: E = None
        self.y: E = None
        self.s: B = None
        self.w: A = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: G = None
        self.t: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: F = None
        self.x: F = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: A = None
        self.q: B = None
        self.x: C = None
        self.r: E = None
        self.s: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.x: B = None
        self.w: F = None
        self.txt = txt

d = A("d")
b = B("b")
i = C("i")
g = D("g")
a = E("a")
c = F("c")
m = G("m")
h = B("h")
l = E("l")
j = A("j")

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

class B:
    def __init__(self, txt: str):
        self.r: G = None
        self.t: B = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.q: F = None
        self.w: F = None
        self.x: F = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: A = None
        self.q: B = None
        self.x: C = None
        self.r: E = None
        self.s: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.x: B = None
        self.w: F = None
        self.txt = txt

d = A("d")
b = B("b")
i = C("i")
g = D("g")
a = E("a")
c = F("c")
m = G("m")
h = B("h")
l = E("l")
j = A("j")

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