#include <fstream>
#include <algorithm>

using namespace std;

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

#define NMAX 100001

int n, i, x, y, m;
long long sum;
struct nanu {
    long long secv, s, d, total;
}arbore[4 * NMAX];

static inline void update(int a, int b, int nod, int poz, int val) {
    if(a == b) {
        arbore[nod].secv = arbore[nod].s = arbore[nod].d = arbore[nod].total = val; 
    }else {
        int mid = (a + b) / 2;
        if(poz <= mid)
            update(a, mid, nod * 2, poz, val);
        else update(mid + 1, b, nod * 2 + 1, poz, val);

        arbore[nod].secv = max(arbore[nod * 2].secv, max(arbore[nod * 2 + 1].secv, arbore[nod * 2].d + arbore[nod * 2 + 1].s));
        arbore[nod].s = max(arbore[nod * 2].s, arbore[nod * 2 + 1].s + arbore[nod * 2].total);
        arbore[nod].d = max(arbore[nod * 2 + 1].d, arbore[nod * 2].d + arbore[nod * 2 + 1].total);
        arbore[nod].total = arbore[nod * 2].total + arbore[nod * 2 + 1].total;
    }
} 

static inline long long query(int a, int b, int nod, int st, int dr) {
    long long x1 = -NMAX, x2 = -NMAX;
    if(st <= a && b <= dr) {
        if(sum < 0)
            sum = 0;
        long long a =  max(arbore[nod].secv, arbore[nod].s + sum); 
        sum = max(sum + arbore[nod].total, arbore[nod].d);
        return a;
    }
    int mid = (a + b) / 2;
    if(st <= mid)
        x1 = query(a, mid, nod * 2, st, dr);
    if(mid < dr)
        x2 = query(mid + 1, b, nod * 2 + 1, st, dr);

    return  max(x1, x2);
}

int main() {
    for(i = 1; i <= 4 * NMAX; i++)
        arbore[i].secv = arbore[i].s = arbore[i].d = (-4) * NMAX;

    cin >> n >> m;
    for(i = 1; i <= n; i++) {
        cin >> x;   
        update(1, n, 1, i, x);
    }

    for(i = 1; i <= m; i++) {
        cin >> x >> y;
        sum = 0;
        cout << query(1, n, 1, x, y) << '\n';
    }

    return 0;
}