func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string a, b, str;     int n, cont = 0, ca = 0, cb = 0;     cin >> a >> b;     n = a.size();     for (int i = 0; i < n; i++) {       if (a[i] != b[i]) cont++;     }     if (cont % 2 == 0) {       for (int i = 0; i < n; i++) {         if (a[i] != b[i]) {           if (ca > cb)             cb++, str += b[i];           else             ca++, str += a[i];         } else           str += a[i];       }       cout << str << endl;     } else       printf( impossible n );   }   