func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long i, n, lns, t = 0, pos = -1, posl = 0;     string s, ot;     cin >> s;     lns = s.length();     ot.clear();     for (i = 0; i < lns; ++i) {       if (s[i] ==  a )         t++;       else         posl++;     }     if (t == lns) {       cout << s;       return 0;     }     if (posl & 1) {       cout <<  :( ;       return 0;     }     t = 0;     for (i = 0; i < lns; ++i) {       if (s[i] !=  a ) t++;       if (t * 2 > posl) {         pos = i;         break;       }     }     for (i = pos; i < lns; ++i) {       if (s[i] ==  a ) {         cout <<  :( ;         return 0;       }     }     i = 0;     t = pos;     while (i < pos) {       if (s[i] ==  a )         i++;       else if (s[i] != s[t]) {         cout <<  :( ;         return 0;       } else         i++, t++;     }     for (i = 0; i < pos; ++i) {       cout << s[i];     }     cout << ot;     return 0;   }   