#include <bits/stdc++.h>

using namespace std;

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

int main(){
    ios::sync_with_stdio(false);
    fin.tie(nullptr);
    fout.tie(nullptr);
    int n,q,st,dr;
    fin>>n>>q;
    vector<int>v(n);
    for (auto &x:v) cin>>x;
    while (q--) {
        fin>>st>>dr;
        st--;
        dr--;
        long long int maxs,s;
        maxs=s=(-1LL<<60);
        for (int i=st;i<=dr;i++) {
            if (s+v[i]>v[i]) s+=v[i];
            else s=v[i];
            maxs=max(maxs,s);
        }
        fout<<maxs<<'\n';
    }
    return 0;
}