import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int q = sc.nextInt();
        int[] values = new int[n];
        int[] counts = new int[n + 1];
        TreeMap<Long, Integer> map = new TreeMap<>();
        long prev = 0;
        for (int i = 0; i < n; i++) {
            map.put(prev, i);
            values[i] = sc.nextInt();
            prev += (long)values[i] * (values[i] + 1) / 2;
            counts[i + 1] = counts[i] + values[i];
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < q; i++) {
            long s = sc.nextInt();
            if (prev < s) {
                sb.append("-1\n");
                continue;
            }
            long current = map.lowerKey(s);
            int idx = map.get(current);
            int x = counts[idx];
            long left = 0;
            long right = values[idx];
            while (right - left > 1) {
                long m = (left + right) / 2;
                if (m * (m + 1) / 2 + current < s) {
                    left = m;
                } else {
                    right = m;
                }
            }
            sb.append(x + right).append("\n");
        }
        System.out.print(sb);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}