import java.io.*;
import java.util.*;
import java.util.function.*;
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();
        long[] sums = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            sums[i] = sums[i - 1] + sc.nextInt();
        }
        long[] sumsum = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            sumsum[i] = sumsum[i - 1] + sums[i];
        }
        String result = IntStream.range(0, q).mapToObj(a -> {
            int target = sc.nextInt();
            if (sumsum[n] < target) {
                return "-1";
            }
            int left = 0;
            int right = n;
            while (right - left > 1) {
                int m = (left + right) / 2;
                if (sumsum[m] < target) {
                    left = m;
                } else {
                    right = m;
                }
            }
            int low = 0;
            int high = n;
            long current = sumsum[right - 1];
            while (high - low > 1) {
                int m = (low + high) / 2;
                if (current + sums[m] < target) {
                    low = m;
                } else {
                    high = m;
                }
            }
            return String.valueOf((right - 1L) * right / 2 + high);
        }).collect(Collectors.joining("\n"));
        System.out.println(result);
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}