using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using System.Text;
//using static CompLib.CompLib;
//using DataStructure;

namespace atcoder
{
    class Program
    {
        const int intMax = 1000000000;
        const long longMax = 2000000000000000000;
        static void Main(string[] args)
        {
            var NQ = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var A = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var P = new long[(NQ[0] * (NQ[0] + 1)) / 2];
            int idx = 0;
            for (int i = 1; i <= NQ[0]; i++)
            {
                int temp = 1;
                for (int j = 0; j < i; j++)
                {
                    P[idx] = temp;
                    idx++;
                    temp++;
                }
            }
            var sum = new long[P.Length + 1];
            for (int i = 1; i <= P.Length; i++)
            {
                sum[i] = sum[i - 1] + P[i - 1];
            }
            while (NQ[1]-- > 0)
            {
                int S = int.Parse(Console.ReadLine());
                int l = 0;
                int r = P.Length;
                while (r - l > 1)
                {
                    int mid = (l + r) / 2;
                    if (sum[mid] >= S)
                    {
                        r = mid;
                    }
                    else
                    {
                        l = mid;
                    }
                }
                if (sum[r] < S) Console.WriteLine(-1);
                else Console.WriteLine(r);
            }
        }
    }
}