<>;
for(<>){
	($a,$b,$c)=split;
	($a,$c)=($c,$a)if$a>$c;
	$a-=$x=$a==$c;
	$y=$b>2?($-=$c-($b-1))+0+($-=$a-($b-2)):inf;
	$z=$a>1?($-=$b-($a-1)):inf;
	$x+=$y<$z?$y:$z;
	print!$a|$x==inf?-1:$x,$/;
}