func_code_string: #include <bits/stdc++.h>   using namespace std;   using ll = long long;   using db = double;   int mod = 1000000007;   db pie = 3.1415926535;   int spf[5000005];   int mm = 5000000;   int pre[5000005];   void help() {     int i;     for (i = 1; i <= mm; i++) {       spf[i] = i;     }     for (i = 2; i <= mm; i += 2) {       spf[i] = 2;     }     int j;     for (i = 3; i * i <= mm; i += 2) {       if (spf[i] == i) {         for (j = i * i; j <= mm; j += i) {           if (spf[j] == j) spf[j] = i;         }       }     }     pre[0] = 0;     pre[1] = 0;     for (i = 2; i <= mm; i++) {       int m = i;       int cnt = 0;       while (m > 1) {         cnt++;         m = m / spf[m];       }       pre[i] = cnt;       pre[i] += pre[i - 1];     }   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     int t;     cin >> t;     help();     while (t--) {       int a, b;       cin >> a >> b;       int ans = pre[a] - pre[b];       cout << ans <<   n ;     }   }   