#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define rc(s) return cout<<s,0
#define pi pair <int, int>
#define sz(x) (int)((x).size())
#define int long long

const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};

const ll inf = 2e9;
const ll mod = 998244353;
const int N = 2e5 + 11;
const int NMAX = 1e4 + 11;
const ll INF64 = 3e18 + 1;
const double eps = 1e-14;
const double PI = acos(-1);

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

int n, T, a[N];

struct yes{
    ll mx,sum,l,r;
};

yes t[4*N];

yes combine(yes A,yes B){

    yes x;

    x.sum = A.sum + B.sum;
    x.l = max({A.l, A.sum + B.l});
    x.r = max({B.r, B.sum + A.r});
    x.mx = max({A.mx,B.mx, A.r + B.l});

    return x;
}

void build(int v, int l, int r){

    if(l == r){
        t[v].l = t[v].r = t[v].sum = t[v].mx = a[l];
    }else{
        int mid = (l + r) >> 1;
        build(2*v,l,mid);
        build(2*v + 1, mid + 1, r);
        t[v] = combine(t[2*v],t[2*v + 1]);
    }
}

yes querry(int v, int tl, int tr, int l, int r){

    if(l <= tl && tr <= r){
        return t[v];
    }

    int mid = (tl + tr) >> 1;

    if(r <= mid){
        return querry(2*v, tl, mid, l, r);
    }

    if(l > mid){
        return querry(2*v + 1, mid + 1, tr, l, r);
    }

    return combine(querry(2*v, tl, mid, l, r),querry(2*v + 1, mid + 1, tr, l, r));
}


int32_t main(){
ios_base :: sync_with_stdio(0); in.tie(); out.tie();

    //cout << setprecision(20) << fixed;

    in >> n >> T;

    for(int i = 1; i <= n; i++){
        in >> a[i];
    }

    build(1,1,n);

    while(T--){

        int x, y;
        in >> x >> y;

        out << querry(1,1,n,x,y).mx << '\n';
    }

}