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

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 + 1];
        long[] sums = new long[n + 1];
        long[] sumsums = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            values[i] = sc.nextInt();
            sums[i] = sums[i - 1] + values[i];
            sumsums[i] = sumsums[i - 1] + sums[i];
        }
        StringBuilder sb = new StringBuilder();
        while (q-- > 0) {
            int s = sc.nextInt();
            if (sumsums[n] < s) {
                sb.append("-1\n");
                continue;
            }
            int left = 0;
            int right = n;
            while (right - left > 1) {
                int m = (left + right) / 2;
                if (s > sumsums[m]) {
                    left = m;
                } else {
                    right = m;
                }
            }
            int idx = left * (left + 1) / 2;
            s -= sumsums[left];
            right = left + 1;
            left = 0;
            while (right - left > 1) {
                int m = (left + right) / 2;
                if (s <= sums[m]) {
                    right = m;
                } else {
                    left = m;
                }
            }
            sb.append(idx + right).append("\n");
        }
        System.out.print(sb);
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    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 int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}