func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( O3 )   #pragma GCC optimize( Ofast )   #pragma GCC target( sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native )   using namespace std;   string a, b;   signed main() {     ios_base::sync_with_stdio(0);     cin.tie();     cout.tie();     cin >> a;     b += a;     reverse(a.begin(), a.end());     b += a;     cout << b;   }   