func_code_string: #include <bits/stdc++.h>   long long int MAX(long long int a, long long int b) {     if (a > b)       return a;     else       return b;   }   using namespace std;   int main() {     string S, SS;     cin >> S >> SS;     int PR = 0, DIF = 0, l = S.length();     for (int x = 0; x < l; x++)       if (S[x] != SS[x]) DIF++;     if (DIF & 1)       printf( impossible n );     else {       DIF /= 2;       bool SEC = false;       for (int i = 0; i < l; i++) {         if (S[i] == SS[i])           printf( 1 );         else {           if (PR == DIF) SEC = true;           if (!SEC) {             if (S[i] ==  1 )               printf( 0 );             else               printf( 1 );           } else {             if (SS[i] ==  1 )               printf( 0 );             else               printf( 1 );           }           PR++;         }       }       printf(  n );     }     return 0;   }   