sub max{$_[$_[1]>$_[0]]}
sub min{$_[$_[1]<$_[0]]}
$\=$/;

($W,$H)=glob<>;
if($W%2==0 && $H%2==0){
	print(min($W,$H)*(max($W,$H)+1)+($W!=$H))
}elsif($W%2==1 && $H%2==1){
	print(($W+1)*($H+1)-min($W,$H))
}else{
	if($W%2==0){
		print($W*($H+1)+1)
	}else{
		print($H*($W+1)+1)
	}
}