func_code_string: #include <bits/stdc++.h>   using namespace std;   char a[100005], ans[100005];   int main() {     int n, m;     cin >> n;     while (n--) {       cin >> a;       m = strlen(a);       for (int i = 0; i < m; i++) {         if (a[i] !=  ? ) {           if (ans[i] == 0)             ans[i] = a[i];           else if (a[i] != ans[i])             ans[i] =  ? ;         }       }     }     ans[m] = 0;     for (int i = 0; i < m; i++) {       if (ans[i] == 0) ans[i] =  a ;     }     cout << ans << endl;     return 0;   }   