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())
    if s>b[-1]:
        print(-1)
        continue
    ind=bisect.bisect_right(b,s)
    if ind==0:
        ok=a[0];ng=0
        while ok-ng>1:
            mid=(ok+ng)//2
            if mid*(mid+1)//2>=s:
                ok=mid
            else:
                ng=mid
        print(ok)
        continue
    s-=b[ind-1]
    if s==0:
        print(a_ind[ind-1])
        continue
    ok=a[ind];ng=0
    while ok-ng>1:
        mid=(ok+ng)//2
        if mid*(mid+1)//2>=s:
            ok=mid
        else:
            ng=mid
    print(a_ind[ind-1]+ok)