func_code_string: #include <bits/stdc++.h>   using namespace std;   map<char, int> m;   int main() {     string s;     cin >> s;     int x = 0;     for (int i = 0; i < s.size(); i++) {       if (m[s[i]] == 0) x++;       m[s[i]]++;     }     if (x > 4 || x < 2)       cout <<  No  << endl;     else if (x == 2) {       for (int i = 0; i < s.size(); i++) {         if (m[s[i]] < 2) {           cout <<  No  << endl;           return 0;         }       }       cout <<  Yes  << endl;     } else if (x == 3) {       if (s.size() >= 4)         cout <<  Yes  << endl;       else         cout <<  No  << endl;     } else if (x == 4) {       cout <<  Yes  << endl;     }   }   