#include <bits/stdc++.h>
using namespace std;
template <class T>
struct FenwickTree1D {
  vector<T> bit;
  int n;
  FenwickTree1D(int a) {
    this->n = a + 1;
    bit.assign(a + 1, 0);
  }
  FenwickTree1D(vector<T> a) : FenwickTree1D(a.size()) {
    for (size_t i = 0; i < a.size(); i++) add(i, a[i]);
  }
  T sum(int idx) {
    T ret = 0;
    for (++idx; idx > 0; idx -= idx & -idx) ret += bit[idx];
    return ret;
  }
  T sum(int l, int r) { return sum(r) - sum(l - 1); }
  void add(int idx, T delta) {
    for (++idx; idx < n; idx += idx & -idx) bit[idx] += delta;
  }
  void range_add(int l, int r, int val) {
    add(l, val);
    add(r + 1, -val);
  }
};
int a[300009];
FenwickTree1D<int> T(300009);
vector<pair<int, int>> query[300009];
int ans[300009];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, q;
  cin >> n >> q;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    a[i] = i - a[i];
  }
  int i = 0;
  while (i++ < q) {
    int x, y;
    cin >> x >> y;
    query[n - y].push_back({x + 1, i});
  }
  for (i = 1; i <= n; i++) {
    if (a[i] >= 0) {
      int lo = 1, hi = i, mid, maxx = 0;
      while (lo <= hi) {
        mid = (lo + hi) / 2;
        int val = T.sum(mid);
        if (val >= a[i]) {
          maxx = mid;
          lo = mid + 1;
        } else
          hi = mid - 1;
      }
      if (maxx) T.range_add(1, maxx, 1);
    }
    for (auto u : query[i]) ans[u.second] = T.sum(u.first);
  }
  for (i = 1; i <= q; i++) cout << ans[i] << '\n';
}
