func_code_string: #include <bits/stdc++.h>   using namespace std;   int _I() {     int x;     scanf( %d , &x);     return x;   }   const int lmt = 10000000;   bool prime[lmt + 5];   int rng = 1, v[lmt + 5];   void sv() {     v[0] = 2;     for (int i = 4; i <= lmt; i += 2) prime[i] = 1;     for (int i = 3; i <= lmt; i += 2) {       if (!prime[i]) {         v[rng++] = i;         for (int j = i * 3; j <= lmt; j += i << 1) prime[j] = 1;       }     }     prime[1] = 1;   }   int rev(int n) {     int num = 0;     while (n) {       num *= 10;       num += (n % 10);       n /= 10;     }     return num;   }   void solve() {     int n = _I();     int ans[100001];     for (int i = 13, j = 1; j <= 11184; i++) {       if (i != rev(i) && !prime[i] && !prime[rev(i)]) ans[j++] = i;     }     cout << ans[n] <<   n ;   }   int main() {     sv();     solve();     return 0;   }   