func_code_string: #include <bits/stdc++.h>   using namespace std;   bitset<300000010> su;   int main() {     su[1] = 1;     int l, r, ans = 0;     cin >> l >> r;     if (l < 3 && r > 1) ans++;     for (int i = 3; i * i <= r; i += 2)       if (!su[i])         for (long long j = 1LL * i * i; j <= r; j += i << 1) su[j] = 1;     while (l % 4 != 1) l++;     for (int i = l; i <= r; i += 4)       if (!su[i]) ans++;     cout << ans;     return 0;   }   