#include <bits/stdc++.h>

using namespace std;

int lft[400000], rght[400000], any[400000], sum[400000], v[100001];
void build(int nod, int left, int right) {
    if(left == right) {
        lft[nod] = rght[nod] = any[nod] = v[left];
        sum[nod] = v[left];
        return;
    }
    int mid = (left + right) / 2;
    build(2 * nod, left, mid);
    build(2 * nod + 1, mid + 1, right);
    lft[nod] = max(lft[2 * nod], sum[2 * nod] + lft[2 * nod + 1]);
    rght[nod] = max(rght[2 * nod] + sum[2 * nod + 1], rght[2 * nod + 1]);
    any[nod] = max(max(any[2 * nod], any[2 * nod + 1]), rght[2 * nod] + lft[2 * nod + 1]);
    sum[nod] = sum[2 * nod] + sum[2 * nod + 1];

}
void query(int nod, int left, int right, int a, int b, int &suma, int &ans) {
    if(left >= a && right <= b) {

        ans = max(max(suma + lft[nod], suma + any[nod]), ans);
        suma = max(max(suma + sum[nod], rght[nod]), 0);
        return;
    }
    int mid = (left + right) / 2;
    if(a <= mid) {
        query(2 * nod, left, mid, a, b, suma, ans);
    }
    if(b > mid) {
        query(2 * nod + 1, mid + 1, right, a, b, suma, ans);
    }
}
int main()
{
    freopen("sequencequery.in", "r", stdin);
    freopen("sequencequery.out", "w", stdout);
    int n, m;
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++) {
        scanf("%d", &v[i]);
    }
    build(1, 1, n);
    int a, b, ans, suma;
    for(int i =0; i < m; i++) {
        ans = -999999;
        suma = 0;
        scanf("%d %d", &a, &b);
        query( 1, 1 , n, a ,b, suma, ans);
        printf("%d\n", ans);

    }
    return 0;
}