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

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

class C:
    def __init__(self, txt: str):
        self.p: B = None
        self.v: D = None
        self.o: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: F = None
        self.q: A = None
        self.o: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.z: A = None
        self.t: E = None
        self.w: D = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: B = None
        self.v: D = None
        self.o: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: F = None
        self.q: A = None
        self.o: A = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.z: A = None
        self.t: E = None
        self.w: D = None
        self.txt = txt

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

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

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