#include <bits/stdc++.h>
#pragma GCC optimize ("O3,unroll-loops")
using namespace std;

int a[100005], v[100005];
signed main()
{
    ifstream cin("sequencequery.in");
    ofstream cout("sequencequery.out");
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);

    int n, q, st, dr, k=0, maxnr=INT_MIN;
    long long s;
    cin>>n>>q;
    for(int i=1; i<=n; i++)
    cin>>a[i];
    while(q--)
    {
        cin>>st>>dr;k=0;
        for(int i=st; i<=dr; i++)
            v[++k]=a[i];
        s=0;maxnr=INT_MIN;
        for(int i=1; i<=k; i++)
        {
            if(s<0)
                s=0;
            s+=v[i];
            if(s>maxnr)
                maxnr=s;
        }
        cout<<maxnr<<'\n';
    }

    return 0;
}