#include <bits/stdc++.h>
using namespace std;
int main()
{
    int N, Q;
    cin >> N >> Q;
    vector<int> V = {0};
    for (int i = 0; i < N; i++)
    {
        int a;
        cin >> a;
        for (int j = 1; j <= a; j++)
            V.push_back(V.back() + j);
    }
    for (int i = 0; i < Q; i++)
    {
        int s;
        cin >> s;
        auto it = lower_bound(V.begin(), V.end(), s);
        if (it == V.end())
            cout << -1 << endl;
        else
            cout << it - V.begin() << endl;
    }
}