func_code_string: #include <bits/stdc++.h>   using namespace std;   int n = 5000001;   void okms() {     vector<int> kk(n);     kk[0] = 0, kk[1] = 0;     for (int(i) = 2; i < n; ++i) kk[i] = 1;     vector<bool> ch(n);     for (int(i) = 0; i < n; ++i) ch[i] = true;     ch[0] = 0, ch[1] = 0;     vector<int> trr(n);     for (int i = 2; i * i <= n - 1; i++) {       if (ch[i]) {         trr[i] = i;         for (int j = i * i; j <= n - 1; j += i) {           ch[j] = false;           trr[j] = i;         }       }     }     for (int(i) = 2; i < n; ++i) {       if (!ch[i]) {         kk[i] = kk[trr[i]] + kk[i / trr[i]];       }     }     vector<int> ans(n);     for (int(i) = 1; i < n; ++i) ans[i] += ans[i - 1] + kk[i];     int t;     cin >> t;     while (t--) {       int a, b;       cin >> a >> b;       cout << ans[a] - ans[b] <<   n ;     }     return;   }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int test;     test = 1;     while (test--) {       okms();     }     return 0;   }   