func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long int n;     cin >> n;     int flag = 0;     while (flag == 0 && n != 0) {       if ((n % 10) == 1)         n = n / 10;       else if ((n % 10) == 4) {         if (((n / 10) % 10) == 1)           n = n / 100;         else if (((n / 10) % 10) == 4) {           if (((n / 100) % 10) == 1)             n = n / 1000;           else             flag = 1;         } else           flag = 1;       } else         flag = 1;     }     if (flag == 1)       cout <<  NO ;     else       cout <<  YES ;     return 0;   }   