#include<iostream>
#include<vector>
using namespace std;

int main() {
    int n, q;
    cin >> n >> q;
    vector<int> a(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    vector<long long> b;
    for (int i = 0; i < n; i++) {
        for (int j = 1; j <= a[i]; j++) {
            b.push_back(j);
        }
    }
    for (int i = 1; i < (int)b.size(); i++) {
        b[i] += b[i - 1];
    }
    for (int i = 0; i < q; i++) {
        long long s;
        cin >> s;
        auto itr = lower_bound(b.begin(), b.end(), s);
        if (itr == b.end()) cout << -1 << endl;
        else {
            int idx = distance(b.begin(), itr);
            cout << idx + 1 << endl;
        }
    }
    return 0;
}