program water; var konec:boolean; i:integer; x,y,s:real; begin repeat read(x); read(y); if x=0 then if y=0 then konec:=true; if not konec then begin s:=3.1415926*(sqr(x)+sqr(y))/2; if s<50 then s:=50; writeln(s/50:1:0); end; until konec; end.