varc,r,s:real;beginwrite('dlina okruznosti=');readln(c);
r:=c/(2*pi);s:=pi*sqr(r);
writeln('ploshad=',s)end.
var
c,r,s:real;
begin
write('dlina okruznosti=');
readln(c);
r:=c/(2*pi);
s:=pi*sqr(r);
writeln('ploshad=',s)
end.