#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 5;
int n, q;
int citations[MAXN];
int fenwick[MAXN];
void update(int idx, int val) {
while (idx <= n) {
fenwick[idx] += val;
idx += idx & -idx;
}
}
int query(int idx) {
int sum = 0;
while (idx > 0) {
sum += fenwick[idx];
idx -= idx & -idx;
}
return sum;
}
int calculate_h_index(int l, int r) {
// Create frequency array for the range
vector<int> freq(n + 1, 0);
for (int i = l; i <= r; i++) {
freq[min(citations[i], n)]++;
}
// Calculate cumulative sum from end
int total_papers = 0;
for (int h = n; h >= 0; h--) {
total_papers += freq[h];
if (total_papers >= h) {
return h;
}
}
return 0;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// Read input
cin >> n >> q;
// Read citations
for (int i = 1; i <= n; i++) {
cin >> citations[i];
}
// Process queries
while (q--) {
int l, r;
cin >> l >> r;
// Calculate and output h-index for the range
cout << calculate_h_index(l, r) << "\n";
}
return 0;
}
