inf=0x70000000
f='e>=0?e:0'
read
while
	read a b c
do
	echo $[
	a>c?t=a,a=c,c=t:0,
	a-=x=a==c,
	y=b>2?(e=c-(b-1),f)+(e=a-(b-2),f):inf,
	z=a>1?(e=b-(a-1),f):inf,
	x+=y<z?y:z,
	!a|x>=inf?-1:x
	]
done