#pragma GCC optimize("Ofast")
#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
#include <deque>
#include <stack>
#include <sstream>
#include <utility>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <tuple>
#include <array>
#include <bitset>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}
inline double time() {
    return static_cast<long double>(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count()) * 1e-9;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,q; cin >> n >> q;
    vector<int> a(n);
    int m = 0;
    for(int i=0;i<n;i++){
        cin >> a[i];
        m += a[i];
    }
    vector<ll> sum(m+1);
    for(int i=1,j=0;j<n;j++){
        for(int k=1;k<=a[j];k++,i++){
            sum[i] = sum[i-1] + k;
        }
    }
    while(q--){
        ll s; cin >> s;
        if(sum[m] < s){
            cout << -1 << "\n";
        }
        else{
            cout << lower_bound(sum.begin(), sum.end(), s) - sum.begin() << "\n";
        }
    }
}