#include <iostream>
#include <fstream>

#define nMax 100000
#define ll long long

using namespace std;

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

int n, m, v[nMax], x, y;
ll aib[nMax];

ll query(int x, int y){
    ll maxim=0;
    for(int i=x;i<=y;i++){
        for(int j=i+1;j<=y;j++){
            if(aib[j]-aib[i-1]>maxim)
                maxim=aib[j]-aib[i-1];
        }
    }
    return maxim;
}

int main()
{
    fin>>n>>m;

    fin>>v[0];
    aib[0]=v[0];

    for(int i=1;i<n;i++){
        fin>>v[i];
        aib[i]=aib[i-1]+v[i];
    }

    for(int i=0;i<m;i++){
        fin>>x>>y;
        x--;
        y--;
        if(x==y)
            fout<<v[x];
        else
            fout<<query(x, y)<<"\n";
    }

    return 0;
}