#include <stdio.h>
#include <vector>
using namespace std;

typedef long long ll;
struct un_nod
{
	ll s_st, s_dr, s_max, s_tot;
};

int n, pos, val, seq_start, seq_end;
ll maxim, dreapta;
vector<un_nod> arb;

void solve();
void update(int, int, int);
void query(int, int, int);
inline ll max(ll, ll);
inline ll max(ll, ll, ll);

int main()
{
	solve();
	return 0;
}

void solve()
{
	int m;
	FILE *fin = fopen("sequencequery.in", "r");
	FILE *fout = fopen("sequencequery.out", "w");
	fscanf(fin, "%d%d", &n, &m);
	arb.resize(4 * n);

	for (pos = 1; pos <= n; ++pos)
	{
		fscanf(fin, "%d", &val);
		update(1, 1, n);
	}
	
	for (; m; --m)
	{
		fscanf(fin, "%d%d", &seq_start, &seq_end);
		maxim = -100000;
		dreapta = -100000;
		query(1, 1, n);
		fprintf(fout, "%lld\n", maxim);
	}
	
	fclose(fin);
	fclose(fout);
}

void update(int nod, int st, int dr)
{
	un_nod &p = arb[nod];
	if (st == dr)
	{
		p.s_st = p.s_dr = val;
		p.s_max = p.s_tot = val;
	}
	else
	{
		un_nod &p2 = arb[2*nod], &p3 = arb[2*nod+1];
		int mid = (st + dr) / 2;
		if (pos <= mid)
		{
			update(2 * nod, st, mid);
		}
		else
		{
			update(2 * nod + 1, mid + 1, dr);
		}
		p.s_tot = p2.s_tot + p3.s_tot;
		p.s_st = max(p2.s_tot + p3.s_st, p2.s_st);
		p.s_dr = max(p3.s_tot + p2.s_dr, p3.s_dr);
		p.s_max = max(p2.s_max, p3.s_max, p2.s_dr + p3.s_st);
	}
}

void query(int nod, int st, int dr)
{
	if (seq_start <= st && dr <= seq_end)
	{
		un_nod p = arb[nod];
		maxim = max(maxim, p.s_max, dreapta + p.s_st);
		dreapta = max(arb[nod].s_dr, dreapta + arb[nod].s_tot);
	}
	else
	{
		int mid = (st + dr) / 2;
		if (seq_start <= mid)
		{
			query(2 * nod, st, mid);
		}
		if (mid < seq_end)
		{
			query(2 * nod + 1, mid + 1, dr);
		}
	}
}

inline ll max(ll a, ll b)
{
	return ((a > b) ? a : b);
}

inline ll max(ll a, ll b, ll c)
{
	return ((a > b) ? ((a > c) ? a : c) : ((b > c) ? b : c));
}