func_code_string: #include <bits/stdc++.h>   #pragma comment(linker, ”/ STACK : 38777216“   using namespace std;   const int N = 100005;   const int inf = 1000 * 1000 * 1000;   const int mod = 1000 * 1000 * 1000 + 7;   string s;   int a, b, c, d, t;   int main() {     cin >> t >> s;     if (t % 4 != 0) {       cout <<  ===  << endl;       return 0;     }     t /= 4;     for (int i = 0; i < 4 * t; i++) {       if (s[i] ==  A ) a++;       if (s[i] ==  C ) b++;       if (s[i] ==  G ) c++;       if (s[i] ==  T ) d++;     }     if (a > t || b > t || c > t || d > t) {       cout <<  ===  << endl;       return 0;     }     a = t - a;     b = t - b;     c = t - c;     d = t - d;     for (int i = 0; i < 4 * t; i++) {       if (s[i] !=  ? ) continue;       if (a > 0) {         s[i] =  A ;         a--;         continue;       }       if (b > 0) {         s[i] =  C ;         b--;         continue;       }       if (c > 0) {         s[i] =  G ;         c--;         continue;       }       s[i] =  T ;       d--;     }     cout << s << endl;     return 0;   }   