import bisect
from itertools import accumulate
n,q=map(int,input().split())
a=list(map(int,input().split()))
a_ind=list(accumulate(a))
b=[]
for i in a:
    b.append(i*(i+1)//2)
b=list(accumulate(b))
for _ in range(q):
    s=int(input())
    ind=bisect.bisect_right(b,s)
    if ind==n and b[ind-1]<s:
        print(-1)
        continue
    s-=b[ind-1]
    ans=a_ind[ind-1]
    ng=-1;ok=a[ind]
    while ok-ng>1:
        mid=(ok+ng)//2
        if mid*(mid+1)//2>=s:
            ok=mid
        else:
            ng=mid
    ans+=ok
    print(ans)