#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

ll B[101010], S[101010];

int main() {
  int N, Q; cin >> N >> Q;
  int n = 0, p = 0;
  for (int i = 0; i < N; i++) {
    int a; cin >> a;
    n += a;
    for (int j = 1; j <= a; j++) {
      B[p++] = j;
    }
  }
  for (int i = 0; i <= n; i++) S[i + 1] = S[i] + B[i];
  while (Q--) {
    ll s; cin >> s;
    int ok = n + 1, ng = -1;
    while (abs(ok - ng) > 1) {
      int mid = (ok + ng) / 2;
      if (S[mid] >= s) ok = mid;
      else ng = mid;
    }
    cout << (ok == n + 1 ? -1: ok) << endl;
  }
  return 0;
}