func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   char s[256];   int vis[8];   int main() {     while (~scanf( %d , &n)) {       scanf( %s , s);       int len = strlen(s);       if (n % 4) {         printf( === n );         continue;       }       for (int i = 0; i < n; i++) {         if (s[i] ==  A )           vis[0]++;         else if (s[i] ==  C )           vis[1]++;         else if (s[i] ==  G )           vis[2]++;         else if (s[i] ==  T )           vis[3]++;       }       int ave = n / 4;       for (int i = 0; i < 4; i++) {         if (vis[i] > ave) {           printf( === n );           return 0;         }       }       for (int i = 0; i < len; i++) {         if (s[i] ==  ? ) {           if (vis[0] < ave) {             printf( A );             vis[0]++;             continue;           } else if (vis[1] < ave) {             printf( C );             vis[1]++;             continue;           } else if (vis[2] < ave) {             printf( G );             vis[2]++;             continue;           } else if (vis[3] < ave) {             printf( T );             vis[3]++;             continue;           }         } else           printf( %c , s[i]);       }       printf(  n );     }     return 0;   }   