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

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

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: F = None
        self.o: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: C = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.s: F = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: F = None
        self.o: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: C = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.s: F = None
        self.txt = txt

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

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