Pi
=
3.14
;
r
=
float
(
input
(
'20'
));
s2
=
Pi
*
r
*
r
;
r
=
r
+
20
;
s1
=
Pi
*
r
*
r
;
s
=
s1
-
s2
;
print
(
'20'
,
s
):