#include <bits/stdc++.h>   using namespace std;   int main() {     string s;     cin >> s;     for (int i = 0; i < s.size(); i++) {       if (s[i] ==  1 ) continue;       if (s[i] ==  4  && s[i - 1] ==  1 ) continue;       if (s[i] ==  4  && i > 1 && s[i - 1] ==  4  && s[i - 2] ==  1 ) continue;       return cout <<  NO , 0;     }     cout <<  YES ;   }   