#include"bits/stdc++.h"
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(x) x.begin(),x.end()

using namespace std;
using ll = long long;

int main(){
    ll n, q;
    cin >> n >> q;
    vector<ll>b;
    b.push_back(0);
    rep(i, n) {
        ll a;
        cin >> a;
        rep(j, a) {
            b.push_back(b.back() + j + 1);
        }
    }
    rep(idx, q) {
        ll s;
        cin >> s;

        auto itr = lower_bound(ALL(b), s);
        if(itr == b.end()) cout << -1 << endl;
        else cout << itr - b.begin() << endl;
    }
}