func_code_string: #include <bits/stdc++.h>   using namespace std;   void fun(long long int n) {     int count = 0;     while (n) {       if (n % 10 == 7 || n % 10 == 4) count++;       n = n / 10;     }     if (count == 0) {       cout <<  NO ;       return;     }     while (count) {       int r = count % 10;       if (r != 7 && r != 4) {         cout <<  NO ;         return;       }       count = count / 10;     }     cout <<  YES ;     return;   }   int main() {     long long int n;     cin >> n;     fun(n);     return 0;   }   