func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string s;     cin >> s;     vector<string> ans;     string email =   ;     bool isPoss = true;     for (int i = 0; i < s.length(); i++) {       if (s[i] ==  @ ) {         if ((i + 1 < s.length()) && (s[i + 1] !=  @ )) {           if (email ==   ) {             isPoss = false;             break;           } else {             email += s[i];             email += s[i + 1];             ans.push_back(email);             i++;             email =   ;           }         } else {           isPoss = false;           break;         }       } else {         email += s[i];       }     }     if ((email !=   ) && (isPoss) && (ans.size() > 0)) {       ans[ans.size() - 1] = ans[ans.size() - 1] + email;     }     if ((ans.size() == 0) || (!isPoss)) {       cout <<  No solution ;     } else {       cout << ans[0];       for (int i = 1; i < ans.size(); i++) {         cout <<  ,  << ans[i];       }     }   }   