func_code_string: #include <bits/stdc++.h>   using namespace std;   int X[1000000], F[100000], i, j, x, y, k, N = 1000000;   int main() {     int n;     cin >> n;     for (i = 1; i < N; i++) X[i] = 1;     for (i = 2; i < N; i++)       if (X[i] == 1) {         j = i + i;         while (j < N) {           X[j] = 0;           j += i;         }       }     for (i = 2; i < N; i++)       if (X[i] == 1) {         x = i;         y = 0;         while (x > 0) {           y *= 10;           y += (x % 10);           x /= 10;         }         if ((X[y] == 1) && (i != y)) {           k++;           F[k] = i;         }       }     cout << F[n] << endl;   }   