class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.o: F = None
        self.p: C = None
        self.r: B = None
        self.u: E = None
        self.y: C = None
        self.t: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: G = None
        self.u: G = None
        self.x: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: G = None
        self.v: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: G = None
        self.t: C = None
        self.w: C = None
        self.v: G = None
        self.z: E = None
        self.u: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: A = None
        self.x: B = None
        self.t: A = None
        self.u: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.r: G = None
        self.q: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.q: A = None
        self.x: C = None
        self.t: D = None
        self.o: D = None
        self.r: F = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: G = None
        self.u: G = None
        self.x: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: G = None
        self.v: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: G = None
        self.t: C = None
        self.w: C = None
        self.v: G = None
        self.z: E = None
        self.u: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: A = None
        self.x: B = None
        self.t: A = None
        self.u: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.r: G = None
        self.q: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.q: A = None
        self.x: C = None
        self.t: D = None
        self.o: D = None
        self.r: F = None
        self.txt = txt

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

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