// In the name of God, the Most Gracious, the Most Merciful.
// @yavuzskarahan - iflbot();
#include <bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(0); cin.tie(0);
#define file(x) freopen(x ".in", "r", stdin); freopen(x ".out", "w", stdout);
#define FOR(i, L, R) for (int i = (L); i <= (R); i++)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
#define int long long
#define ll long long
#define pb push_back
#define ub(v, a) upper_bound((v).begin(), (v).end(), (a))
#define lb(v, a) lower_bound((v).begin(), (v).end(), (a))
#define f first
#define s second
#define tm (tl+(tr-tl)/2)
#define space << " " <<
#define vi vector<int>
#define pii pair<int,int>
#define vpii vector<pair<int,int>>
#define now chrono::high_resolution_clock::now()
const long long N = 2e5+5;
const long long M = 3e6+5;
const long long K = 23;
const long long SQRTN = sqrt(N);
const long long MOD = 1e9+7;
inline int sum(int a, int b) {return ((a%MOD)+(b%MOD))%MOD;}
inline int mul(int a, int b) {return ((a%MOD)*(b%MOD))%MOD;}
inline int epow(int n, int us){int cvp = 1; while(us){if (us%2){cvp *= n;}n *= n; us /= 2;} return cvp;}
int n, q, l, r, a[N];
vi sgt[4*N];
inline bool compare(const int& a, const int& b){
return a < b;
}
inline vi merge(const vi& a, const vi& b){
vi result(a.size()+b.size());
merge(a.begin(), a.end(), b.begin(), b.end(), result.begin(), compare);
return result;
}
inline void build(int v, int tl, int tr) {
if (tl == tr) {sgt[v].pb(a[tl]); return;}
build(2*v, tl, tm);
build(2*v+1, tm+1, tr);
sgt[v] = merge(sgt[2*v], sgt[2*v+1]);
}
inline int query(int v, int tl, int tr, int l, int r, int mid) {
if (tr < l || tl > r) return 0;
if (l <= tl && tr <= r){
auto it = lb(sgt[v], mid);
if ((*it) == mid) it--;
return sgt[v].end() - it; // num of mid <=
}
return query(2*v, tl, tm, l, r, mid) + query(2*v+1, tm+1, tr, l, r, mid);
}
inline int h(int currl, int currr){
r = currr-currl+1;
l = 1;
int hIndex = 0;
while(l<=r){
int m = l+(r-l)/2;
if (query(1,1,n,currl,currr,m) >= m) {hIndex = m; l = m+1;}
else r = m-1;
}
return hIndex;
}
inline int solve() {
cin >> n >> q;
FOR(i,1,n) cin >> a[i];
build(1,1,n);
while (q--) {
cin >> l >> r;
cout << h(l,r) << endl;
}
return 0;
}
int32_t main() {
#ifdef LOCAL
auto start = now;
#endif
fast;
int t = 1;
//cin >> t;
while(t--){
solve();
}
#ifdef LOCAL
auto end = now;
chrono::duration<double> elapsed = end - start;
cout << endl << "runtime: " << endl << elapsed.count() << endl;
#endif
return 0;
}
