func_code_string: #include <bits/stdc++.h>   using namespace std;   template <class A, class B>   ostream &operator<<(ostream &out, const pair<A, B> &a) {     return out <<  (  << a.first <<  ,  << a.second <<  ) ;   }   template <class A>   ostream &operator<<(ostream &out, const vector<A> &a) {     for (const A &it : a) out << it <<    ;     return out;   }   template <class A, class B>   istream &operator>>(istream &in, pair<A, B> &a) {     return in >> a.first >> a.second;   }   template <class A>   istream &operator>>(istream &in, vector<A> &a) {     for (A &i : a) in >> i;     return in;   }   ifstream cinn( in.txt );   ofstream coutt( out.txt );   int poww(const int &a, int b, const int &m = (1000000007)) {     if (b == 0) return 1;     int x = poww(a, b / 2, m);     x = x * x % m;     if (b & 1) x = x * a % m;     return x;   }   int ceil(const int &a, const int &b) { return (a - 1) / b + 1; }   int primes[5000005];   signed main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     for (int i = 2; i < 5000005; i++) {       if (primes[i]) continue;       for (int j = i; j < 5000005; j += i) {         int in = j;         while (in % i == 0) {           in /= i;           primes[j]++;         }       }     }     for (int i = 1; i < 5000005; i++) primes[i] += primes[i - 1];     int t;     cin >> t;     while (t--) {       int a, b;       cin >> a >> b;       cout << primes[a] - primes[b] <<   n ;     }   }   