func_code_string: #include <bits/stdc++.h>   using namespace std;   int cmpint(const void *a, const void *b) {     if (((int *)a)[0] == ((int *)b)[0]) return ((int *)a)[1] - ((int *)b)[1];     return ((int *)a)[0] - ((int *)b)[0];   }   int prim[500005] = {0};   bool isprim[5000005] = {0};   int prim_len;   void count_prim() {     int i, j, l;     prim[0] = 2;     prim_len = 1;     for (i = 3; i < 5000000; i += 2)       if (isprim[i] == 0) {         prim[prim_len] = i;         prim_len++;         l = i * 2;         if (i < 10000)           for (j = i * i; j < 5000000; j += l) isprim[j] = 1;       }   }   int a[100005];   int main() {     int i, j, n, m, k, l, o, p;     scanf( %d , &n);     count_prim();     m = 0;     for (i = (0); i < (prim_len); i++) {       k = prim[i];       l = 0;       while (k > 0) {         l = l * 10 + k % 10;         k /= 10;       }       if (l != prim[i] && isprim[l] == 0 && l % 2 == 1) {         m++;         a[m] = prim[i];       }       if (m > n) break;     }     printf( %d n , a[n]);     return 0;   }   