#include <bits/stdc++.h>
#define ll long long

using namespace std;

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

const ll INF = -1e12;
const int NMAX = 1e6 + 3;

int n, q;
int v[NMAX];

struct Node {
    ll seg, pref, suff, sum;
} t[3 * NMAX];

Node combine(Node a, Node b) {
    Node c;
    c.sum = a.sum + b.sum;
    c.pref = max(a.pref, a.sum + b.pref);
    c.suff = max(b.suff, b.sum + a.suff);
    c.seg = max(max(a.seg, b.seg), a.suff + b.pref);
    return c;
}

void build(int node, int l, int r) {
    if(l == r) {
        t[node] = {v[l], v[l], v[l], v[l]};
        return;
    }
    int mid = (l + r) / 2;
    build(2 * node, l, mid);
    build(2 * node + 1, mid + 1, r);
    t[node] = combine(t[2 * node], t[2 * node + 1]);
}

Node query(int node, int l, int r, int x, int y) {
    if(r < x || l > y) { return {INF, INF, INF, INF}; }
    if(x <= l && r <= y) { return t[node]; }
    int mid = (l + r) / 2;
    Node a = query(2 * node, l, mid, x, y);
    Node b = query(2 * node + 1, mid + 1, r, x, y);
    return combine(a, b);
}


int main() {

    in >> n >> q;

    for(int i = 1; i <= n; i++) {
        in >> v[i];
    }

    build(1, 1, n);

    while(q--) {
        int x, y;
        in >> x >> y;
        out << query(1, 1, n, x, y).seg << '\n';
    }

    return 0;
}