i
t
e
r
a
t
i
o
n
s
t
e
p
-
3
-
2
-
1
1
2
-
2
0
-
1
5
-
1
0
-
5
5
1
0
f
(
x
)
I
t
e
r
a
t
i
o
n
=
0
x
_
n
=
0
.
f
(
x
_
n
)
=
3
.
