func_code_string: #include <bits/stdc++.h>   using namespace std;   int sc1() {     int x;     scanf( %d , &x);     return x;   }   long long sc2() {     long long x;     scanf( %lld , &x);     return x;   }   int bs;   int n, q;   int arr[100007];   int cnt[100007];   int ans = 0;   int answer[100007];   struct A {     int l, r, id;   } node[100007];   bool cmp(A a, A b) {     int x = a.l / bs;     int y = b.l / bs;     if (x != y) return x < y;     return a.r < b.r;   }   void add(int x) {     if (x <= n) {       if (cnt[x] == x) ans--;       cnt[x]++;       if (cnt[x] == x) ans++;     }   }   void rmv(int x) {     if (x <= n) {       if (cnt[x] == x) ans--;       cnt[x]--;       if (cnt[x] == x) ans++;     }   }   int main() {     n = sc1(), q = sc1();     bs = sqrt(n);     for (int i = 0; i < n; i++) arr[i] = sc1();     for (int i = 0; i < q; i++) {       int a = sc1(), b = sc1();       node[i].l = --a;       node[i].r = --b;       node[i].id = i;     }     sort(node, node + q, cmp);     int mo_left = 0, mo_right = -1;     for (int i = 0; i < q; i++) {       int left = node[i].l;       int right = node[i].r;       while (mo_right < right) {         mo_right++;         add(arr[mo_right]);       }       while (mo_right > right) {         rmv(arr[mo_right]);         mo_right--;       }       while (mo_left < left) {         rmv(arr[mo_left]);         mo_left++;       }       while (mo_left > left) {         mo_left--;         add(arr[mo_left]);       }       answer[node[i].id] = ans;     }     for (int i = 0; i < q; i++) {       cout << answer[i] << endl;     }     return 0;   }   