func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, k;     cin >> n >> k;     string inp;     cin >> inp;     bool found = false;     for (int i = 0; (i < n - 1) && k; ++i) {       if (inp[i] ==  4  && inp[i + 1] ==  7 ) {         if (((i + 1) & 1) && (i < n - 2) && (inp[i + 2] ==  7 )) {           if (k & 1) inp[i + 1] =  4 ;           cout << inp << endl;           found = true;           break;         } else if ((((i + 1) & 1) == 0) && (i) && (inp[i - 1] ==  4 )) {           if (k & 1) inp[i] =  7 ;           cout << inp << endl;           found = true;           break;         } else if (((i + 1) & 1)) {           inp[i + 1] =  4 ;           --k;         } else if (((i + 1) % 2) == 0) {           inp[i] =  7 ;           --k;         }       }     }     if (!found) cout << inp << endl;     return 0;   }   