from itertools import accumulate
from bisect import bisect_left


def main():
    n, q = map(int, input().split())
    a = list(map(int, input().split()))
    acc1 = list(accumulate(a))
    acc2 = list(accumulate(acc1))

    for _ in range(q):
        s = int(input())
        if s > acc2[-1]:
            print(-1)
            continue

        k = bisect_left(acc2, s)
        if s == acc2[k]:
            print((k + 1) * (k + 2) // 2)
            continue

        left = -1
        right = k
        while right - left > 1:
            mid = (right + left) // 2
            if acc1[mid] >= s - acc2[k - 1]:
                right = mid
            else:
                left = mid
        print(k * (k + 1) // 2 + right)


if __name__ == "__main__":
    main()