#include <fstream>

using namespace std;

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

int arr[100001];

long long query ( int x, int y ) {

    long long res = -100001;
    long long aux = 0;

    for (int i = x; i <= y; i++) {
        if ( arr[i] > aux + arr[i] )
            aux = arr[i];
        else
            aux = aux + arr[i];

        res = max ( aux, res );
    }

    return res;
}

void solve () {

    int n, m;
    fin >> n >> m;

    for ( int i = 1; i <= n; i++ )
        fin >> arr[i];

    int x, y;
    while ( m-- ) {
        fin >> x >> y;
        fout << query (x, y) << "\n";
    }
}

int main()
{
    solve ();
    return 0;
}