/* -*- coding: utf-8 -*-
 *
 * 1890.cc:  No.1890 Many Sequences Sum Queries - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 100;
const int MAX_M = 100000;

/* typedef */

typedef long long ll;

/* global variables */

int as[MAX_N];
ll ss[MAX_M + 1];

/* subroutines */

/* main */

int main() {
  int n, qn;
  scanf("%d%d", &n, &qn);

  for (int i = 0; i < n; i++) scanf("%d", as + i);

  ss[0] = 0;
  int m = 1;
  for (int i = 0; i < n; i++)
    for (int j = 1; j <= as[i]; j++, m++)
      ss[m] = ss[m - 1] + j;
  //for (int i = 0; i < m; i++) printf("%lld ", ss[i]); putchar('\n');

  while (qn--) {
    int si;
    scanf("%d", &si);

    int k = lower_bound(ss, ss + m, si) - ss;
    printf("%d\n", (k >= m) ? -1 : k);
  }
  return 0;
}