#include"bits/stdc++.h"
#include<experimental/iterator>
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(x) x.begin(),x.end()
#define BACK(x) x.rbegin(),x.rend()
#define MOD1 1000000007
#define MOD2 998244353
#define INF INT_MAX
#define INFL (LLONG_MAX / 2)
#define FLOAT_ANS setprecision(30)
#define TORAD(x) (x*acos(-1)/180.0)
#define TODEG(x) (x*180/acos(-1))

using namespace std;
using ll = long long;
using ull = unsigned long long;

template<typename T> // T:重み
using p_que = priority_queue<T,vector<T>,greater<T>>;

template<typename T>
bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}

template<typename T>
bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}

ll modpow(ll a, ll n, ll mod) {ll res=1;while (n>0) {if(n&1)res=(res*(a%mod))%mod;a=((a%mod)*(a%mod))%mod;n>>=1;}return res;}

template<typename T>
void RotateVec2(vector<vector<T>>&v){ll h=v.size();ll w=v[0].size();vector<vector<T>>t(w,vector<T>(h));rep(i,h){rep(j,w){t[j][h-i-1]=v[i][j];}}v=t;}

bool InRange(ll x, ll mn, ll mx){return (mn <= x && x <= mx);}

template<typename T>
void printVec(vector<T>&v,string str=" "){copy(ALL(v),experimental::make_ostream_joiner(cout, str));}

template<typename T>
vector<T>&merged(vector<T>&a,vector<T>&b) {vector<T>res;merge(a.begin(),a.end(),b.begin(),b.end(),back_inserter(res));return res;}

struct UnionFind{
    vector<ll>tree;
    UnionFind(ll x):tree(x, -1){}
    ll root(ll x){if(tree[x]<0) return x;return tree[x]=root(tree[x]);}
    bool same(ll x,ll y){return root(x)==root(y);}
    ll size(ll x){return -tree[root(x)];}
    void unite(ll x,ll y){x=root(x),y=root(y);if(x==y)return;if(size(x)<size(y))swap(x,y);tree[x]+=tree[y];tree[y]=x;}
};

template<typename T>
struct SegTree{
    ll e,n;vector<T>tree;function<T(T,T)>f;
    SegTree(ll n_,function<T(T,T)>f_,T e_=0):e(e_),f(f_){ll x=1;while(x<n_)x*=2;n=x;tree.assign(n*2,e);}
    void update(ll idx,T x){idx+=n-1;tree[idx]=x;while(idx){idx=(idx-1)/2;tree[idx]=f(tree[idx*2+1],tree[idx*2+2]);}}
    T query(ll x,ll y){return query_sub(x,y,0,n,0);}
    T query_sub(ll x,ll y,ll l,ll r,ll k){if(r<=x||y<=l)return e;if(x<=l&&r<=y)return tree[k];ll c1=query_sub(x,y,l,(l+r)/2,k*2+1);ll c2=query_sub(x,y,(l+r)/2,r,k*2+2);return f(c1,c2);}
    void print(){cout<<"---"<<endl;for(ll idx=0,t=1;auto i:tree){if(idx+1==n*2)break;cout<<i<<" ";++idx;if(idx+1==1<<t){++t;cout<<endl;}}cout<<"---"<<endl;}
};

template <std::uint_fast64_t Modulus> class modint {
    using u64 = std::uint_fast64_t;
public:
    u64 a;
    constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr modint operator+(const modint rhs) const noexcept {return modint(*this) += rhs;}
    constexpr modint operator-(const modint rhs) const noexcept {return modint(*this) -= rhs;}
    constexpr modint operator*(const modint rhs) const noexcept {return modint(*this) *= rhs;}
    constexpr modint operator/(const modint rhs) const noexcept {return modint(*this) /= rhs;}
    constexpr modint &operator+=(const modint rhs) noexcept {a += rhs.a;if (a >= Modulus) {a -= Modulus;}return *this;}
    constexpr modint &operator-=(const modint rhs) noexcept {if (a < rhs.a) {a += Modulus;}a -= rhs.a;return *this;}
    constexpr modint &operator*=(const modint rhs) noexcept {a = a * rhs.a % Modulus;return *this;}
    constexpr modint &operator/=(modint rhs) noexcept {u64 exp = Modulus - 2;while (exp) {if (exp % 2) {*this *= rhs;}rhs *= rhs;exp /= 2;}return *this;}
    constexpr modint &operator=(u64 x){ a = x % Modulus; return *this; }
};

// MAIN PROGRAM ------------

int main(){
    ll n, q;
    cin >> n >> q;
    vector<ll>b;
    b.push_back(0);
    rep(i, n) {
        ll a;
        cin >> a;
        rep(j, a) {
            b.push_back(b.back() + j + 1);
        }
    }
    rep(idx, q) {
        ll s;
        cin >> s;

        auto itr = lower_bound(ALL(b), s);
        if(itr == b.end()) cout << -1 << endl;
        else cout << itr - b.begin() << endl;
    }
}