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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.p: G = None
        self.t: F = None
        self.o: F = None
        self.s: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: C = None
        self.o: G = None
        self.v: B = None
        self.x: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.u: C = None
        self.z: C = None
        self.t: A = None
        self.r: F = None
        self.txt = txt

l = A("l")
i = B("i")
j = C("j")
g = D("g")
b = E("b")
k = F("k")
c = G("c")
m = E("m")
e = A("e")

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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.p: G = None
        self.t: F = None
        self.o: F = None
        self.s: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: C = None
        self.o: G = None
        self.v: B = None
        self.x: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: C = None
        self.u: C = None
        self.z: C = None
        self.t: A = None
        self.r: F = None
        self.txt = txt

l = A("l")
i = B("i")
j = C("j")
g = D("g")
b = E("b")
k = F("k")
c = G("c")
m = E("m")
e = A("e")

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