#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++)
#define srep(i,a,b) for(int i = a; i < b; i++)
#define all(A) (A).begin(),A.end()
#define MOD 1000000007
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
using Graph = vector<vector<int>>;
int siz(string s){return (int)s.size();}

ll B[101010],S[101010];
int main(void){
	int n,q; cin >> n >> q;
	int nn = 0;
	int p = 0;
	rep(i,n){
		int a; cin >> a;
		nn += a;
		rep(j,a) B[p] = j+1,p++;
	}
	rep(i,nn+1) S[i+1] = S[i]+B[i];

	rep(i,q){
		ll s; cin >> s;
		int ans = 0;
		rep(j,nn+1){
			if(S[ans] >= s) break;
			ans++;
		}
		cout << (ans == nn+1 ? -1 : ans) << endl;
	}
	return 0;
}