#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cmath>
#include<set>
#include<stack>
#include<deque>
#include<cassert>
//#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(int)(n); i++)
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
typedef long long ll;
typedef pair<int,int> P;
using Graph = vector<vector<int>>;
//#define INF 10000000
class UnionFind{
    public:
    vector<int> par;

    UnionFind(int n) : par(n){
        for(int i=0; i<n; i++) par[i] = -1;
    }

    int root(int x){
        if(par[x] == -1) return x;
        int next = par[x];
        return root(next);
    }

    void unite(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return;
        par[px] = py;
    }

    bool same(int x, int y){
        int px = root(x);
        int py = root(y);
        if(px == py) return true;
        else return false; 
    }
};



bool isPrime(int x){
    bool prime = true;
    for(int i=2; i<x; i++){
        if(x%i == 0){
            prime = false;
            break;
        }
    }
    if(!prime) return false;
    return true;
}


//------------------------------------------------------------------------//

vector<int> p;
vector<int> sum;

bool isOk(int mid,int key){
    if(sum[mid] >= key) return true;
    return false;
}

int main(){
    int n,q;
    cin >> n >> q;
    vector<int> a(n);
    rep(i,n) cin >> a[i];
    rep(i,n){
        for(int j=1; j<=a[i]; j++){
            p.emplace_back(j);
        }
    }
    /*
    for(auto it : p){
        cout << it << ":";
    }
    puts("");
    */
    int tmp = 0;
    sum.emplace_back(0);
    for(auto it : p){
        tmp += it;
        sum.emplace_back(tmp);
    }
    /*
    for(auto it : sum) cout << it << endl;
    puts("");
    */
    ///query
    vector<int> ans;
    rep(i,q){
        int s;
        cin >> s;
        int right = sum.size()+1;
        int left = -1;
        while(right - left > 1){
            int mid = (right + left)/2;
            if(isOk(mid,s)) right = mid;
            else left = mid;
        }
        if(left == sum.size()){
            ans.emplace_back(-1);
            continue;
        }
        ans.emplace_back(right);
    }
    for(auto it : ans) cout << it << endl;
    return 0;
}