n=int(input())
i=0
while i<n:
    j,total,e=0,0,0
    money,k,m=map(int,input().split())
    s=list(map(int,input().split()))
    s.sort()
    while j<k:
        total=total+int(s[j])
        j=j+1
    if total > money:
        e=total-money
    else:
        e=0
    print(e)
    i=i+1