#include <bits/stdc++.h>
#define TIME false
using namespace std;
using namespace std::chrono;
const int MAXN = 2e5;
vector <int> tree[4*MAXN+1];
void build(int now, int l, int r, const vector <int> &arr) {
if (l == r) {
tree[now].push_back(arr[l-1]);
return ;
}
int mid = (l+r)>>1;
int left = now<<1;
int right = left|1;
build (left, l, mid, arr);
build(right, mid+1, r, arr);
merge(tree[left].begin(), tree[left].end(), tree[right].begin(), tree[right].end(), back_inserter(tree[now]));
}
int query(int now, int l, int r, const int i, const int j, const int x) {
if (l > j || r < i) return 0;
if (i <= l && j >= r) {
int idx = lower_bound(tree[now].begin(), tree[now].end(), x)-tree[now].begin();
return r-l+1-idx;
}
int mid = (l+r)>>1;
return query(now<<1, l, mid, i, j, x)
+query(now<<1|1, mid+1, r, i, j, x);
}
int main(int argc, const char* argv[]) {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, q;
cin >> n >> q;
vector <int> arr(n);
for(int i = 0; i < n; ++i) {
cin >> arr[i];
}
#if TIME
double elapsed;
high_resolution_clock::time_point start = high_resolution_clock::now();
#endif
build(1, 1, n, arr);
while (q--) {
int l, r;
cin >> l >> r;
int left = 1, right = MAXN;
int best = 0;
while (left <= right) {
int x = (left+right)>>1;
int cnt = query(1, 1, n, l, r, x);
if (cnt >= x && x >= best) {
best = x;
left = x+1;
}
else right = x-1;
}
cout << best << '\n';
}
#if TIME
high_resolution_clock::time_point finish = high_resolution_clock::now();
duration<double> time_span = duration_cast<duration<double>>(finish-start);
elapsed = time_span.count();
#endif
//arr.clear();
//for(int i = 0; i <= (MAXN<<2); ++i) tree[i].clear();
#if TIME
cout << fixed << setprecision(10) << elapsed << " seconds\n";
#endif
return 0;
}
