#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

using mint = modint998244353;

void debug_mint1(vector<mint> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        cerr << vec[i].val() << " ";
    }
    cerr << endl;
}

void debug_mint2(vector<vector<mint>> &vec) {
    for (int i = 0; i < vec.size(); i++) {
        for (int j = 0; j < vec[i].size(); j++) {
            cerr << vec[i][j].val() << " ";
        }
        cerr << endl;
    }
}

int main() {
    ll N, Q;
    cin >> N >> Q;
    vector<ll> A(N);
    rep(i, N){
        cin >> A[i];
    }
    vector<ll> sum_a(N + 1, 0);
    rep(i, N){
        sum_a[i + 1] = sum_a[i] + A[i];
    }
    vector<ll> sum_b(N + 1, 0);
    rep(i, N){
        sum_b[i + 1] = sum_b[i] + sum_a[i + 1];
    }
    debug(sum_b);
    vector<ll> sum_siz(N + 1, 0);
    rep(i, N){
        sum_siz[i + 1] = sum_siz[i] + i + 1;
    }
    vector<ll> L(Q);
    vector<ll> R(Q);
    rep(i, Q){
        cin >> L[i] >> R[i];
    }
    rep(i, Q){
        // R 番目までの和　から L - 1 番目までの和　を引く、と考える
        ll sum_r = 0;
        if (R[i] == N * (N + 1) / 2){
            sum_r = sum_b[N];
        }
        else{
            auto it = upper_bound(all(sum_siz), R[i]);
            it--;
            ll id = it - sum_siz.begin();
            sum_r += sum_b[id];
            ll rem = R[i] - sum_siz[id];
            sum_r += sum_a[rem];
            // debug_out(id, rem);
        }

        ll sum_l = 0;
        auto it = upper_bound(all(sum_siz), L[i] - 1);
        it--;
        ll id = it - sum_siz.begin();
        sum_l += sum_b[id];
        ll rem = L[i] - 1 - sum_siz[id];
        sum_l += sum_a[rem];

        cout << sum_r - sum_l << endl;
    }
}