#include <bits/stdc++.h>
#define int long long
using namespace std;
const int INF = 1e9;
const int NMAX = 1e5+2;
int n,q,v[NMAX];

ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");

struct Node{
    int sum = -INF, pref = -INF, suff = -INF, ssm = -INF;
    Node(){}
    Node(int x){
        sum = pref = suff = ssm = x;
    }
    Node operator + (const Node &aux) const {
        Node ans;
        if(sum == -INF){
            return aux;
        }
        ans.sum = sum+aux.sum;
        ans.pref = max(pref, sum+aux.pref);
        ans.suff = max(aux.suff, aux.sum+suff);
        ans.ssm = max({ssm, aux.ssm, suff+aux.pref, ans.pref, ans.suff});
        return ans;
    }
} aint[4*NMAX];

void build(int nod, int st, int dr){
    if(st == dr){
        aint[nod] = v[st];
    }else{
        int mid = (st+dr)/2;
        build(2*nod, st, mid);
        build(2*nod+1, mid+1, dr);
        aint[nod] = aint[2*nod] + aint[2*nod+1];
    }
}

Node query(int nod, int st, int dr, int l, int r){
    if(l <= st && dr <= r){
        return aint[nod];
    }else{
        int mid = (st+dr)/2;
        Node ans;
        if(l <= mid){
            ans = ans+query(2*nod, st, mid, l, r);
        }
        if(r >= mid+1){
            ans = ans+query(2*nod+1, mid+1, dr, l, r);
        }
        return ans;
    }
}

signed main()
{
    fin >> n >> q;
    for(int i = 1; i <= n; i++){
        fin >> v[i];
    }
    build(1, 1, n);
    while(q--){
        int x, y;
        fin >> x >> y;
        fout << query(1, 1, n, x, y).ssm << "\n";
    }
    return 0;
}