func_code_string: #include <bits/stdc++.h>   using namespace std;   const int INF = 1000000000;   const long long INFLL = 1000000000000000000LL;   const int h = 300000000;   int l, r;   int pr[(h >> 6) + 1];   int main() {     scanf( %d%d , &l, &r);     int res = 0;     int r2 = (r - 1) / 2;     pr[0] |= 1;     for (int i = (1), _b = ((sqrt(2.0 * r2 + 1) + 1) / 2); i < _b; ++i)       if ((~pr[i >> 5]) & (1 << (i & 31)))         for (int i2 = 2 * i + 1, v = i * (i + 1) << 1; v <= r2; v += i2)           pr[v >> 5] |= 1 << (v & 31);     if (l <= 2 && 2 <= r) ++res;     for (int v = 2; v <= r2; v += 2)       if (l <= 2 * v + 1 && (~pr[v >> 5]) & (1 << (v & 31))) ++res;     printf( %d n , res);     return 0;   }   