N,Q = map(int,input().split())
a = list(map(int,input().split()))
c = []
for i in range(N):
    c.append(a[i]*(a[i]+1)//2)

for _ in range(Q):
    s = int(input())
    sum_b = 0
    ANS = 0
    for i in range(N):
        if sum_b+c[i] < s:
            sum_b += c[i]
            ANS += a[i]
        elif sum_b < s:
            for j in range(a[i]):
                ANS += 1
                sum_b += j+1
                if sum_b >= s: break
    if sum_b < s: print(-1)
    else: print(ANS)