#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define ull unsigned ll
#define vec vector
#define flist forward_list
#define um unordered_map
#define us unordered_set
#define prioq priority_queue
#define all(x) x.begin(), x.end()
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define ld long double
#define pll pair<ll, ll>
#define tll tuple<ll, ll, ll>
#define ass assign

#define LL_MAX LLONG_MAX
#define LL_MIN LLONG_MIN
#define ULL_MAX ULLONG_MAX
#define LD_MAX LDBL_MAX
#define LD_MIN LDBL_MIN

#define nl '\n'

#define vv(type, name, n, ...) vector<vector<type>> name(n, vector<type>(__VA_ARGS__))
#define vvv(type, name, n, m, ...)                                                                                     \
    vector<vector<vector<type>>> name(n, vector<vector<type>>(m, vector<type>(__VA_ARGS__)))

// https://trap.jp/post/1224/
#define rep1(n) for(ll i=0; i<(ll)(n); ++i)
#define rep2(i,n) for(ll i=0; i<(ll)(n); ++i)
#define rep3(i,a,b) for(ll i=(ll)(a); i<(ll)(b); ++i)
#define rep4(i,a,b,c) for(ll i=(ll)(a); i<(ll)(b); i+=(c))
#define cut4(a,b,c,d,e,...) e
#define rep(...) cut4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rep1e(n) for(ll i=1; i<=(ll)(n); ++i)
#define rep2e(i,n) for(ll i=1; i<=(ll)(n); ++i)
#define rep3e(i,a,b) for(ll i=(ll)(a); i<=(ll)(b); ++i)
#define rep4e(i,a,b,c) for(ll i=(ll)(a); i<=(ll)(b); i+=(c))
#define repe(...) cut4(__VA_ARGS__,rep4e,rep3e,rep2e,rep1e)(__VA_ARGS__)
#define per1(n) for(ll i=((ll)n)-1; i>=0; --i)
#define per2(i,n) for(ll i=((ll)n)-1; i>=0; --i)
#define per3(i,a,b) for(ll i=((ll)b)-1; i>=(ll)(a); --i)
#define per4(i,a,b,c) for(ll i=((ll)b)-1; i>=(ll)(a); i-=(c))
#define per(...) cut4(__VA_ARGS__,per4,per3,per2,per1)(__VA_ARGS__)
#define per1e(n) for(ll i=((ll)n); i>=1; --i)
#define per2e(i,n) for(ll i=((ll)n); i>=1; --i)
#define per3e(i,a,b) for(ll i=((ll)a); i>=(ll)(b); --i)
#define per4e(i,a,b,c) for(ll i=((ll)a); i>=(ll)(b); i-=(c))
#define pere(...) cut4(__VA_ARGS__,per4e,per3e,per2e,per1e)(__VA_ARGS__)
#define rep_subset(i,s) for(ll i=(s); i>=0; i=(i==0?-1:(i-1)&(s)))
// #define forit(v) for (auto it = v.begin(); it != v.end(); it++)
// #define forit2(it, v) for (auto it = v.begin(); it != v.end(); it++)
// #define forrit(v) for (auto it = v.rbegin(); it != v.rend(); it++)
// #define forrit2(it, v) for (auto it = v.rbegin(); it != v.rend(); it++)

// #ifdef i_am_noob
#define bug(...) cerr << "#" << __LINE__ << ' ' << #__VA_ARGS__ << "- ", _do(__VA_ARGS__)
template<typename T> void _do(vector<vector<T>> x){cerr << "\n"; for(auto i: x) {for(auto j : i) {cerr << j << ' ';} cerr << "\n";}}
template<typename T> void _do(vector<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(unordered_set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(T && x) {cerr << x << endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr << x << ", "; _do(y...);}
// #else
// #define bug(...) 777771449
// #endif

const ll MOD = 1e9 + 7;
const ll INF = (1ll << 59);

const string FILENAME = "sequencequery";
ifstream fin(FILENAME + ".in");
ofstream fout(FILENAME + ".out");

#define cin fin
#define cout fout

struct nodeData
{
	
	ll ans, sum, pref, suf;
	
	void operator=(nodeData& x)
	{
		ans = x.ans;
		sum = x.sum;
		pref = x.pref;
		suf = x.suf;
	}
	void comb(nodeData a, nodeData& b)
	{
		ans = max({a.ans, b.ans, a.suf + b.pref});
		sum = a.sum + b.sum;
		pref = max(a.pref, a.sum + b.pref);
		suf = max(b.suf, b.sum + a.suf);
	}
};

class Hoshino
{
public:

	ll n;
	vec<nodeData> ai;	
	
	void build(vec<ll>& v)
	{
		n = v.size();
		ai.resize(2*n-1);
		build_(0, 0, n-1, v);
	}
	void build_(ll i, ll l, ll r, vec<ll>& v)
	{
		if(l == r)
		{
			ai[i].sum = v[l];
			ai[i].pref = v[l];
			ai[i].suf = v[l];
			ai[i].ans = v[l];
			return;
		}
		
		ll mid = (l+r)/2, rc = i+2*(mid-l+1);
		build_(i+1, l, mid, v);
		build_(rc, mid+1, r, v);
		ai[i].comb(ai[i+1], ai[rc]);
	}
	ll query(ll l, ll r)
	{
		nodeData res;
		queue<ll> sel;
		
		query_(0, 0, n-1, l, r, sel);
		
		res = ai[sel.front()];
		sel.pop();
		
		while(!sel.empty())
		{
			res.comb(res, ai[sel.front()]);
			sel.pop();
		}
		
		return res.ans;
	}
	void query_(ll i, ll l, ll r, ll x, ll y, queue<ll>& sel)
	{
		if(x <= l && r <= y)
		{
			sel.push(i);
			return;
		}
		
		ll mid = (l+r)/2, rc = i+2*(mid-l+1);
		if(x <= mid) query_(i+1, l, mid, x, y, sel);
		if(mid < y) query_(rc, mid+1, r, x, y, sel);
	}
};

int main()
{
	ll n, q;
	cin >> n >> q;
	vec<ll> nums(n); rep(n) cin >> nums[i];
	
	Hoshino ai;
	ai.build(nums);
	
	rep(q)
	{
		ll a, b;
		cin >> a >> b;
		a--, b--;
		cout << ai.query(a, b) << nl;
	}
	
    return 0;
}