t=int(input())
for j in range(t):
	n,k,m=map(int,raw_input().strip().split())
	mo=map(int,raw_input().strip().split())
	mo.sort()
	x=0
	for i in range(k):
		x+=mo[i]
	if n<x:
		print x-n
	else:
		print 0