func_code_string: #include <bits/stdc++.h>   using namespace std;   bool pal(string s) {     string b = s;     reverse(b.begin(), b.end());     return b == s;   }   int main() {     string s;     cin >> s;     for (int i = 0; i <= s.size(); ++i) {       for (char a =  a ; a <=  z ; ++a) {         string b = s.substr(0, i) + a + s.substr(i);         if (pal(b)) {           cout << b << endl;           return 0;         }       }     }     cout <<  NA  << endl;     return 0;   }   