Program qwer;

Var
	k,x,y: integer;
	n,i:longint;
Begin
	randomize;
	k:=0;
	n:=10000;
	for i:=1 to n do 
		begin
		x:=random(4)-2;
		y:=random(4)-2;
		if (x+y<=1) and (x-y<=1) and (-x+y<=1) and (-x-y<=1) then 
			k:=k+1;
		end;
	writeln(k/n*4 :2:2);
End.