#include <bits/stdc++.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <cstdlib>
#include <cmath>
#include <queue>
#include <stack>
#include <deque>
#include <fstream>
#include <iterator>
#include <set>
#include <map>
#include <unordered_map>
#include <iomanip>
#include <cctype>
#include <string>
#include <cassert>
#include <set>
#include <bitset>
#include <unordered_set>
#include <numeric>
#define all(a) a.begin(), a.end()
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define pb push_back
#define ppi pair<int,pair<int,int>>
#define int int64_t
using namespace std;
// /\_/\
// (= ._.)
// / > \>
// encouraging cat
const int INF = 10000000000000000;
//const int mod = 1000000007;
const int mod = 998244353;
const int MAXN = 2002;
//ifstream fin('xor.in');
//ofstream fout('xor.out');
int dp[MAXN][MAXN];
signed main()
{
int n,q;
cin >> n >> q;
vector<int> a(n);
for (int i = 0;i < n;i++)
{
cin >> a[i];
}
for (int i = 0;i < n;i++)
{
dp[i][i] = a[i];
}
for (int sz = 2;sz <= n;sz++)
{
for (int i = 0;i < n;i++)
{
int r = i + sz - 1;
if (r >= n)
{
break;
}
int lo = i, hi = r - 1, mid = (lo + hi + 1) / 2;
while (lo < hi)
{
mid = (lo + hi + 1) / 2;
if (dp[i][mid] <= dp[mid + 1][r])
{
lo = mid;
}
else
{
hi = mid - 1;
}
}
dp[i][r] = max(dp[i][lo], dp[lo + 1][r]) + 1;
if (lo < r)
{
dp[i][r] = min(dp[i][r], max(dp[i][lo + 1], dp[lo + 1][r]) + 1);
}
}
}
while (q--)
{
int l,r;
cin >> l >> r;
l--,r--;
cout << dp[l][r] << '\n';
}
return 0;
}
