#include<iostream>
#include<set> 
#include<algorithm>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<numeric>
#include<queue>
#include<cmath>
#include <unordered_set>
using namespace std;
typedef long long ll;
const ll INF=1LL<<60;
typedef pair<ll,ll> P;
typedef pair<int,P> PP;
const ll MOD=1e9+7;

int main(){
    int N,Q;
    cin>>N>>Q;
    vector<int> A(N);
    vector<int> B;
    for(int i=0;i<N;i++){
        cin>>A[i];
        for(int j=1;j<=A[i];j++){
            B.push_back(j);
        }
    }
    int n=B.size();
    vector<ll> sumB(n);
    sumB[0]=B[0];
    for(int i=1;i<n;i++){
        sumB[i]=sumB[i-1]+B[i];
    }

    for(int q=0;q<Q;q++){
        ll S;
        cin>>S;
        auto it=lower_bound(sumB.begin(),sumB.end(),S);

        if(it==sumB.end()){
            cout<<-1<<endl;
        }else{
            int c=it-sumB.begin();
            cout<<c+1<<endl;

        }

    }

}