for tcase in range(int(input())):
    a,b,c=map(int,input().split())
    d=list(map(int,input().split()))
    d.sort()
    total,wxa=0,0
    for i in range(b):
        total=total+d[i]
    if total-a>0:
        print(total-a)
    else:
        print("0")