func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long MAX = 3e5 + 10;   const long long INF = 1e18;   const long long M = 1e6 + 10;   int main() {     int n, i, j, k, l, p, q;     string s;     cin >> n >> s;     set<char> a;     char st[3] = { R ,  G ,  B };     for (i = 0; i < n; i++) a.insert(s[i]);     if (a.size() == 1) {       cout << *a.begin();       return 0;     }     if (n == 2) {       if (s[i] == s[i + 1])         cout << s[i];       else {         for (i = 0; i < 3; i++) {           if (a.find(st[i]) == a.end()) cout << st[i];         }       }     } else {       if (a.size() == 3)         cout <<  BGR ;       else {         char ch;         string s2 =   ;         for (i = 0; i < 3; i++) {           if (a.find(st[i]) == a.end()) ch = st[i];         }         for (i = 0; i < 3; i++) {           l = 0;           for (j = 0; j < n; j++) {             if (s[j] == st[i]) l++;           }           if (l == 1) {             s2 += ch;             s2 += st[i];             sort(s2.begin(), s2.end());             cout << s2;             break;           }         }         if (l != 1) cout <<  BGR ;       }     }   }   