typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
    ll n,q;
    std::cin >> n>>q;
    vector<ll> a(n);
    vector<ll> v;
    ll cur = 0;
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
        for (int j = 1; j <= a[i]; j++) {
            cur += j;
            v.push_back(cur);
        }
    }
    for (int iii = 0; iii < q; iii++) {
        ll s;
        std::cin >> s;
        
        auto it = lower_bound(v.begin(),v.end(),s);
        if(it==v.end()){
            std::cout << -1 << std::endl;
        }else{
            std::cout << it-v.begin()+1 << std::endl;
        }
    }
}