#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("sequencequery.in");
ofstream fout("sequencequery.out");

struct nod {
    long long suma;
    long long  smax;
    long long  smax_st;
    long long  smax_dr;
};

long long  n,m,a,b;
long long  v[100001];
nod aint[4 * 100001];
long long  maxim, ssm_st;

void build(long long  node, long long  st, long long  dr) {
    if (st == dr) {
        aint[node].suma = v[st];
        aint[node].smax = v[st];
        aint[node].smax_st = v[st];
        aint[node].smax_dr = v[st];

        return;
    }

    long long  mijloc = (st + dr) / 2;
    build(node * 2, st, mijloc);
    build(node * 2 + 1, mijloc + 1, dr);

    aint[node].suma = aint[node * 2].suma + aint[node * 2 + 1].suma ;
    aint[node].smax_st = max(aint[node * 2].smax_st, aint[node * 2 + 1].smax_st + aint[node * 2].suma);
    aint[node].smax_dr = max(aint[node * 2 + 1].smax_dr, aint[node * 2].smax_dr + aint[node * 2 + 1].suma);
    aint[node].smax = max(aint[node*2].smax, max(aint[node*2+1].smax, aint[node * 2].smax_dr + aint[node * 2 + 1].smax_st));
}

void query(long long  node, long long  st, long long  dr) {
    if (b >= dr && st >= a) {
        maxim = max(maxim, max(aint[node].smax, aint[node].smax_st + ssm_st));
        ssm_st = max(ssm_st + aint[node].suma, aint[node].smax_dr);
        if (ssm_st < 0)
            ssm_st = 0;
        return;
    }

    long long  mijloc = (st + dr) / 2;

    if (a <= mijloc) {
        query(node * 2, st, mijloc);
    }
    if (b > mijloc) {
        query(node * 2 + 1, mijloc + 1, dr);
    }

}

int main () {
    fin >> n >> m;
    for (long long  i = 1; i<=n; i++) {
        fin >> v[i];
    }

    build(1,1,n);

    for (long long  i = 1; i<=m; i ++) {
        fin >> a >> b;
        query(1,1,n);
        fout << maxim << '\n';
        maxim = -100001;
        ssm_st = 0;
    }

}