func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, k;   char ch[111111];   int main() {     scanf( %d%d , &n, &k);     scanf( %s , ch);     int pos = 0;     for (int act = 0; act <= 1000000 && act < k && pos < n - 1; ++act) {       if (act >= 1000000 && act % 2 == k % 2) break;       while (pos < n - 1 && !(ch[pos] ==  4  && ch[pos + 1] ==  7 )) pos++;       if (pos == n - 1) break;       if (pos % 2 == 0)         ch[pos] = ch[pos + 1] =  4 ;       else         ch[pos] = ch[pos + 1] =  7 ;       --pos;       if (pos < 0) pos = 0;     }     printf( %s n , ch);   }   