func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e5 + 10;   const double eps = 1e-9;   int n, t;   char A[N], B[N];   int main() {     scanf( %d %d n , &n, &t);     gets(A);     gets(B);     int sameCnt = 0;     for (int i = 0; i < n; ++i) {       if (A[i] == B[i]) ++sameCnt;     }     int dif = n - sameCnt;     if (dif / 2 + dif % 2 <= t) {       int wic = 0;       int have = 0;       t -= dif / 2 + dif % 2;       have = dif % 2;       if (t > sameCnt) {         have += 2 * (t - sameCnt);         t = sameCnt;       }       if (n == 1000) {       }       for (int i = 0; i < n; ++i) {         if (have && A[i] != B[i]) {           char tempval =  a ;           for (int j = 0; j < 26; ++j) {             if (tempval + j != A[i] && tempval + j != B[i]) {               printf( %c , tempval + j);               break;             }           }           have--;           continue;         }         if (A[i] != B[i]) {           if (wic)             printf( %c , A[i]);           else             printf( %c , B[i]);           wic = 1 - wic;           continue;         }         if (t > 0 && A[i] == B[i]) {           t--;           char temp = A[i] + 1;           if (A[i] ==  z ) temp =  y ;           printf( %c , temp);         } else {           printf( %c , A[i]);         }       }       printf(  n );     } else {       cout <<  -1  << endl;     }     return 0;   }   